diff --git a/app/helpers/order_helper.rb b/app/helpers/order_helper.rb
index c6ab5807bb..e15b8acdbb 100644
--- a/app/helpers/order_helper.rb
+++ b/app/helpers/order_helper.rb
@@ -6,6 +6,6 @@ module OrderHelper
   end
 
   def outstanding_balance_label(order)
-    order.outstanding_balance.negative? ? t(:credit_owed) : t(:balance_due)
+    order.outstanding_balance.label
   end
 end
diff --git a/app/models/concerns/balance.rb b/app/models/concerns/balance.rb
index 91019d401c..794bb40f9f 100644
--- a/app/models/concerns/balance.rb
+++ b/app/models/concerns/balance.rb
@@ -7,13 +7,28 @@ require 'active_support/concern'
 module Balance
   FINALIZED_NON_SUCCESSFUL_STATES = %w(canceled returned).freeze
 
+  # Branches by the OrderBalance abstraction
+  def outstanding_balance
+    OrderBalance.new(self)
+  end
+
+  # This method is the one we're gradually replacing with `#new_outstanding_balance`. Having them
+  # separate enables us to choose which implementation we want depending on the context using
+  # a feature toggle. This avoids inconsistent behavior during that incremental refactoring.
+  #
+  # It is meant to be removed as soon as we get product approval that the new implementation has
+  # been working correctly in production.
+  def old_outstanding_balance
+    total - payment_total
+  end
+
   # Returns the order balance by considering the total as money owed to the order distributor aka.
-  # the shop, and as a positive balance of said enterprise. If the customer pays it all, they
+  # the shop, and as a positive balance of said enterprise. If the customer pays it all, the
   # distributor and customer are even.
   #
   # Note however, this is meant to be used only in the context of a single order object. When
   # working with a collection of orders, such an index controller action, please consider using
-  # `app/queries/oustanding_balance.rb` instead so we avoid potential N+1s.
+  # `app/queries/outstanding_balance.rb` instead so we avoid potential N+1s.
   def new_outstanding_balance
     if state.in?(FINALIZED_NON_SUCCESSFUL_STATES)
       -payment_total
@@ -22,22 +37,11 @@ module Balance
     end
   end
 
-  # This method is the one we're gradually replacing with `#new_outstanding_balance`. Having them
-  # separate enables us to choose which implementation we want depending on the context using
-  # a feature toggle. This avoids incosistent behavior across the app during that incremental
-  # refactoring.
-  #
-  # It is meant to be removed as soon as we get product approval that the new implementation has
-  # been working correctly in production.
-  def outstanding_balance
-    total - payment_total
-  end
-
   def outstanding_balance?
     !outstanding_balance.zero?
   end
 
   def display_outstanding_balance
-    Spree::Money.new(outstanding_balance, currency: currency)
+    outstanding_balance.amount
   end
 end
diff --git a/app/models/order_balance.rb b/app/models/order_balance.rb
index 58fb03a353..83110c23f3 100644
--- a/app/models/order_balance.rb
+++ b/app/models/order_balance.rb
@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class OrderBalance
+  delegate :zero?, :abs, :to_s, to: :to_f
+
   def initialize(order)
     @order = order
   end
@@ -17,11 +19,13 @@ class OrderBalance
     if customer_balance_enabled?
       order.new_outstanding_balance
     else
-      order.outstanding_balance
+      order.old_outstanding_balance
     end
   end
 
-  delegate :zero?, to: :to_f
+  def +(other)
+    to_f + other.to_f
+  end
 
   private
 
diff --git a/app/serializers/api/order_serializer.rb b/app/serializers/api/order_serializer.rb
index f5e9b001d8..dcd38aa651 100644
--- a/app/serializers/api/order_serializer.rb
+++ b/app/serializers/api/order_serializer.rb
@@ -11,7 +11,7 @@ module Api
       if OpenFoodNetwork::FeatureToggle.enabled?(:customer_balance, object.user)
         -object.balance_value
       else
-        object.outstanding_balance
+        object.old_outstanding_balance
       end
     end
 
diff --git a/engines/order_management/app/services/order_management/order/updater.rb b/engines/order_management/app/services/order_management/order/updater.rb
index 4aac1f7843..b391592577 100644
--- a/engines/order_management/app/services/order_management/order/updater.rb
+++ b/engines/order_management/app/services/order_management/order/updater.rb
@@ -157,8 +157,7 @@ module OrderManagement
       def infer_payment_state_from_balance
         # This part added so that we don't need to override
         # order.outstanding_balance
-        balance = order.outstanding_balance
-        balance = -1 * order.payment_total if canceled_and_paid_for?
+        balance = order.new_outstanding_balance
 
         infer_state(balance)
       end
@@ -184,20 +183,10 @@ module OrderManagement
         order.state_changed('payment')
       end
 
-      # Taken from order.outstanding_balance in Spree 2.4
-      # See: https://github.com/spree/spree/commit/7b264acff7824f5b3dc6651c106631d8f30b147a
-      def canceled_and_paid_for?
-        order.canceled? && paid?
-      end
-
       def canceled_and_not_paid_for?
         order.state == 'canceled' && order.payment_total.zero?
       end
 
-      def paid?
-        payments.present? && !payments.completed.empty?
-      end
-
       def failed_payments?
         payments.present? && payments.valid.empty?
       end
diff --git a/engines/order_management/app/services/order_management/reports/bulk_coop/bulk_coop_report.rb b/engines/order_management/app/services/order_management/reports/bulk_coop/bulk_coop_report.rb
index 1f658b189a..5c54b492d9 100644
--- a/engines/order_management/app/services/order_management/reports/bulk_coop/bulk_coop_report.rb
+++ b/engines/order_management/app/services/order_management/reports/bulk_coop/bulk_coop_report.rb
@@ -171,7 +171,7 @@ module OrderManagement
           if OpenFoodNetwork::FeatureToggle.enabled?(:customer_balance, @user)
             unique_orders(line_items).sum(&:new_outstanding_balance)
           else
-            unique_orders(line_items).sum(&:outstanding_balance)
+            unique_orders(line_items).sum(&:old_outstanding_balance)
           end
         end
 
diff --git a/engines/order_management/spec/services/order_management/reports/bulk_coop/bulk_coop_report_spec.rb b/engines/order_management/spec/services/order_management/reports/bulk_coop/bulk_coop_report_spec.rb
index f667c8fdc6..0fd9d5d0b5 100644
--- a/engines/order_management/spec/services/order_management/reports/bulk_coop/bulk_coop_report_spec.rb
+++ b/engines/order_management/spec/services/order_management/reports/bulk_coop/bulk_coop_report_spec.rb
@@ -195,7 +195,7 @@ describe OrderManagement::Reports::BulkCoop::BulkCoopReport do
       end
 
       it 'calls #outstanding_balance' do
-        expect_any_instance_of(Spree::Order).to receive(:outstanding_balance)
+        expect_any_instance_of(Spree::Order).to receive(:old_outstanding_balance)
         subject.send(:customer_payments_amount_owed, [line_item])
       end
     end
diff --git a/engines/order_management/spec/services/order_management/subscriptions/payment_setup_spec.rb b/engines/order_management/spec/services/order_management/subscriptions/payment_setup_spec.rb
index 32bf3874d0..0cb4ade9e5 100644
--- a/engines/order_management/spec/services/order_management/subscriptions/payment_setup_spec.rb
+++ b/engines/order_management/spec/services/order_management/subscriptions/payment_setup_spec.rb
@@ -9,7 +9,7 @@ module OrderManagement
       let(:payment_setup) { OrderManagement::Subscriptions::PaymentSetup.new(order) }
 
       describe "#call!" do
-        let!(:payment){ create(:payment, amount: 10) }
+        let!(:payment) { create(:payment, amount: 10) }
 
         context "when no pending payments are present" do
           let(:payment_method) { create(:payment_method) }
@@ -17,7 +17,7 @@ module OrderManagement
 
           before do
             allow(order).to receive(:pending_payments).once { [] }
-            allow(order).to receive(:outstanding_balance) { 5 }
+            allow(order).to receive(:old_outstanding_balance) { 5 }
             allow(order).to receive(:subscription) { subscription }
           end
 
@@ -31,14 +31,14 @@ module OrderManagement
           before { allow(order).to receive(:pending_payments).once { [payment] } }
 
           context "when the payment total doesn't match the outstanding balance on the order" do
-            before { allow(order).to receive(:outstanding_balance) { 5 } }
+            before { allow(order).to receive(:old_outstanding_balance) { 5 } }
             it "updates the payment total to reflect the outstanding balance" do
               expect{ payment_setup.call! }.to change(payment, :amount).from(10).to(5)
             end
           end
 
           context "when the payment total matches the outstanding balance on the order" do
-            before { allow(order).to receive(:outstanding_balance) { 10 } }
+            before { allow(order).to receive(:old_outstanding_balance) { 10 } }
 
             it "does nothing" do
               expect{ payment_setup.call! }.to_not change(payment, :amount).from(10)
@@ -51,7 +51,7 @@ module OrderManagement
           let!(:payment2) { create(:payment, order: order) }
 
           before do
-            allow(order).to receive(:outstanding_balance) { 7 }
+            allow(order).to receive(:old_outstanding_balance) { 7 }
             allow(order).to receive(:pending_payments).once { [payment1, payment2] }
           end
 
diff --git a/lib/open_food_network/user_balance_calculator.rb b/lib/open_food_network/user_balance_calculator.rb
index 98af1600f9..5f0fe64f34 100644
--- a/lib/open_food_network/user_balance_calculator.rb
+++ b/lib/open_food_network/user_balance_calculator.rb
@@ -6,7 +6,7 @@ module OpenFoodNetwork
     end
 
     def balance
-      -completed_orders.to_a.sum(&:outstanding_balance)
+      -completed_orders.to_a.sum(&:old_outstanding_balance)
     end
 
     private
diff --git a/spec/controllers/spree/admin/orders/payments/payments_controller_refunds_spec.rb b/spec/controllers/spree/admin/orders/payments/payments_controller_refunds_spec.rb
index d7b67a7988..5ec3543894 100644
--- a/spec/controllers/spree/admin/orders/payments/payments_controller_refunds_spec.rb
+++ b/spec/controllers/spree/admin/orders/payments/payments_controller_refunds_spec.rb
@@ -45,12 +45,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "voids the payment" do
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             spree_put :fire, params
             expect(payment.reload.state).to eq 'void'
             order.reload
             expect(order.payment_total).to eq 0
-            expect(order.outstanding_balance).to_not eq 0
+            expect(order.outstanding_balance.to_f).to_not eq 0
           end
         end
 
@@ -64,12 +64,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "does not void the payment" do
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             expect(flash[:error]).to eq "Bup-bow!"
           end
         end
@@ -104,12 +104,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "partially refunds the payment" do
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to eq order.total
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
           end
         end
 
@@ -123,12 +123,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "does not void the payment" do
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             expect(flash[:error]).to eq "Bup-bow!"
           end
         end
@@ -169,12 +169,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "voids the payment" do
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             spree_put :fire, params
             expect(payment.reload.state).to eq 'void'
             order.reload
             expect(order.payment_total).to eq 0
-            expect(order.outstanding_balance).to_not eq 0
+            expect(order.outstanding_balance.to_f).to_not eq 0
           end
         end
 
@@ -189,12 +189,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "does not void the payment" do
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             expect(flash[:error]).to eq "Bup-bow!"
           end
         end
@@ -211,12 +211,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "can still void the payment" do
             order.reload
             expect(order.payment_total).to_not eq 0
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
             spree_put :fire, params
             expect(payment.reload.state).to eq 'void'
             order.reload
             expect(order.payment_total).to eq 0
-            expect(order.outstanding_balance).to_not eq 0
+            expect(order.outstanding_balance.to_f).to_not eq 0
           end
         end
       end
@@ -252,12 +252,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "partially refunds the payment" do
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to eq order.total
-            expect(order.outstanding_balance).to eq 0
+            expect(order.outstanding_balance.to_f).to eq 0
           end
         end
 
@@ -271,12 +271,12 @@ describe Spree::Admin::PaymentsController, type: :controller do
           it "does not void the payment" do
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             spree_put :fire, params
             expect(payment.reload.state).to eq 'completed'
             order.reload
             expect(order.payment_total).to eq order.total + 5
-            expect(order.outstanding_balance).to eq(-5)
+            expect(order.outstanding_balance.to_f).to eq(-5)
             expect(flash[:error]).to eq "Bup-bow!"
           end
         end
diff --git a/spec/features/admin/customers_spec.rb b/spec/features/admin/customers_spec.rb
index b115d0f98d..87fa500497 100644
--- a/spec/features/admin/customers_spec.rb
+++ b/spec/features/admin/customers_spec.rb
@@ -133,6 +133,11 @@ feature 'Customers' do
         context "with an additional negative payment (or refund)" do
           let!(:payment2) { create(:payment, order: order1, state: 'completed', payment_method: payment_method, response_code: 'pi_123', amount: -25.00) }
 
+          before do
+            order1.user = user
+            order1.save!
+          end
+
           it "displays an updated customer balance" do
             visit spree.admin_order_payments_path order1
             expect(page).to have_content "$#{payment2.amount}"
diff --git a/spec/features/admin/payments_spec.rb b/spec/features/admin/payments_spec.rb
index 2c670c44ee..d6c5f38d66 100644
--- a/spec/features/admin/payments_spec.rb
+++ b/spec/features/admin/payments_spec.rb
@@ -10,10 +10,13 @@ feature '
 
   let(:order) { create(:completed_order_with_fees) }
 
-  scenario "visiting the payment form" do
-    login_as_admin_and_visit spree.new_admin_order_payment_path order
+  describe "payments/new" do
+    it "displays the order balance as the default payment amount" do
+      login_as_admin_and_visit spree.new_admin_order_payment_path order
 
-    expect(page).to have_content "New Payment"
+      expect(page).to have_content I18n.t(:new_payment)
+      expect(page).to have_field(:payment_amount, with: order.outstanding_balance.to_f)
+    end
   end
 
   context "with sensitive payment fee" do
@@ -26,10 +29,10 @@ feature '
       payment_method.save!
     end
 
-    scenario "visiting the payment form" do
+    it "renders the new payment page" do
       login_as_admin_and_visit spree.new_admin_order_payment_path order
 
-      expect(page).to have_content "New Payment"
+      expect(page).to have_content I18n.t(:new_payment)
     end
   end
 end
diff --git a/spec/features/admin/reports/payments_report_spec.rb b/spec/features/admin/reports/payments_report_spec.rb
index b618bae352..11c828593e 100644
--- a/spec/features/admin/reports/payments_report_spec.rb
+++ b/spec/features/admin/reports/payments_report_spec.rb
@@ -5,7 +5,7 @@ require 'spec_helper'
 describe "Payments Reports" do
   include AuthenticationHelper
 
-  let!(:order) do
+  let(:order) do
     create(
       :order_with_distributor,
       state: 'complete',
@@ -13,37 +13,87 @@ describe "Payments Reports" do
       order_cycle: order_cycle
     )
   end
-  let(:order_cycle) { create(:simple_order_cycle) }
-  let!(:line_item) do
-    create(:line_item_with_shipment, order: order, product: product)
+  let(:other_order) do
+    create(
+      :order_with_distributor,
+      state: 'complete',
+      completed_at: Time.zone.now,
+      order_cycle: order_cycle,
+      distributor: order.distributor
+    )
   end
+  let(:order_cycle) { create(:simple_order_cycle) }
   let(:product) { create(:product, supplier: supplier) }
   let(:supplier) { create(:supplier_enterprise) }
 
-  before { login_as_admin }
+  before do
+    create(:line_item_with_shipment, order: order, product: product)
+    create(:line_item_with_shipment, order: other_order, product: product)
 
-  it 'shows orders with payment state, their balance and totals' do
-    visit spree.payments_admin_reports_path
+    login_as_admin
+  end
 
-    select I18n.t(:report_itemised_payment), from: "report_type"
-    find("[type='submit']").click
+  context "when choosing itemised payments report type" do
+    it "shows orders with payment state, their balance and totals" do
+      visit spree.payments_admin_reports_path
 
-    expect(page.find("#listing_orders thead tr").text).to eq([
-      I18n.t(:report_header_payment_state),
-      I18n.t(:report_header_distributor),
-      I18n.t(:report_header_product_total_price, currency: currency_symbol),
-      I18n.t(:report_header_shipping_total_price, currency: currency_symbol),
-      I18n.t(:report_header_outstanding_balance_price, currency: currency_symbol),
-      I18n.t(:report_header_total_price, currency: currency_symbol)
-    ].join(" "))
+      select I18n.t(:report_itemised_payment), from: "report_type"
+      find("[type='submit']").click
 
-    expect(page.find("#listing_orders tbody tr").text).to eq([
-      order.payment_state,
-      order.distributor.name,
-      order.item_total.to_f,
-      order.ship_total.to_f,
-      order.outstanding_balance.to_f,
-      order.total.to_f
-    ].join(" "))
+      expect(page.find("#listing_orders thead tr").text).to eq([
+        I18n.t(:report_header_payment_state),
+        I18n.t(:report_header_distributor),
+        I18n.t(:report_header_product_total_price, currency: currency_symbol),
+        I18n.t(:report_header_shipping_total_price, currency: currency_symbol),
+        I18n.t(:report_header_outstanding_balance_price, currency: currency_symbol),
+        I18n.t(:report_header_total_price, currency: currency_symbol)
+      ].join(" "))
+
+      expect(page.find("#listing_orders tbody tr").text).to eq([
+        order.payment_state,
+        order.distributor.name,
+        order.item_total.to_f + other_order.item_total.to_f,
+        order.ship_total.to_f + other_order.ship_total.to_f,
+        order.outstanding_balance.to_f + other_order.outstanding_balance.to_f,
+        order.total.to_f + other_order.total.to_f
+      ].join(" "))
+    end
+  end
+
+  context 'when choosing payment totals report type' do
+    let(:paypal) { create(:payment_method, name: "PayPal") }
+    let!(:paypal_payment) { create(:payment, order: order, payment_method: paypal, state: "completed", amount: 5) }
+
+    let(:eft) { create(:payment_method, name: "EFT") }
+    let!(:eft_payment) { create(:payment, order: other_order, payment_method: eft, state: "completed", amount: 6) }
+
+    it 'shows orders with payment state, their balance and and payment totals' do
+      visit spree.payments_admin_reports_path
+
+      select I18n.t(:report_payment_totals), from: "report_type"
+      find("[type='submit']").click
+
+      expect(page.find("#listing_orders thead tr").text).to eq([
+        I18n.t(:report_header_payment_state),
+        I18n.t(:report_header_distributor),
+        I18n.t(:report_header_product_total_price, currency: currency_symbol),
+        I18n.t(:report_header_shipping_total_price, currency: currency_symbol),
+        I18n.t(:report_header_total_price, currency: currency_symbol),
+        I18n.t(:report_header_eft_price, currency: currency_symbol),
+        I18n.t(:report_header_paypal_price, currency: currency_symbol),
+        I18n.t(:report_header_outstanding_balance_price, currency: currency_symbol),
+      ].join(" "))
+
+      expect(page.find("#listing_orders tbody tr").text).to eq([
+        order.payment_state,
+        order.distributor.name,
+        order.item_total.to_f + other_order.item_total.to_f,
+        order.ship_total.to_f + other_order.ship_total.to_f,
+        order.total.to_f + other_order.total.to_f,
+        eft_payment.amount.to_f,
+        paypal_payment.amount.to_f,
+        order.outstanding_balance.to_f + other_order.outstanding_balance.to_f,
+      ].join(" "))
+    end
   end
 end
diff --git a/spec/mailers/order_mailer_spec.rb b/spec/mailers/order_mailer_spec.rb
index d23b920c55..ed71ebc308 100644
--- a/spec/mailers/order_mailer_spec.rb
+++ b/spec/mailers/order_mailer_spec.rb
@@ -15,7 +15,7 @@ describe Spree::OrderMailer do
     end
 
     context 'when the order has outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 123 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 123 } }
 
       it 'renders the amount as money' do
         expect(email.body).to include('$123')
@@ -23,7 +23,7 @@ describe Spree::OrderMailer do
     end
 
     context 'when the order has no outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 0 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 0 } }
 
       it 'displays the payment status' do
         expect(email.body).to include(I18n.t(:email_payment_not_paid))
@@ -58,7 +58,7 @@ describe Spree::OrderMailer do
     end
 
     context 'when the order has outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 123 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 123 } }
 
       it 'renders the amount as money' do
         expect(email.body).to include('$123')
@@ -66,7 +66,7 @@ describe Spree::OrderMailer do
     end
 
     context 'when the order has no outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 0 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 0 } }
 
       it 'displays the payment status' do
         expect(email.body).to include(I18n.t(:email_payment_not_paid))
diff --git a/spec/mailers/subscription_mailer_spec.rb b/spec/mailers/subscription_mailer_spec.rb
index 0cd77c047a..3ea46f0d5a 100644
--- a/spec/mailers/subscription_mailer_spec.rb
+++ b/spec/mailers/subscription_mailer_spec.rb
@@ -88,7 +88,7 @@ describe SubscriptionMailer, type: :mailer do
     end
 
     context 'when the order has outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 123 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 123 } }
 
       it 'renders the amount as money' do
         expect(email.body).to include('$123')
@@ -96,7 +96,7 @@ describe SubscriptionMailer, type: :mailer do
     end
 
     context 'when the order has no outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 0 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 0 } }
 
       it 'displays the payment status' do
         expect(email.body).to include(I18n.t(:email_payment_not_paid))
@@ -141,7 +141,7 @@ describe SubscriptionMailer, type: :mailer do
     end
 
     context 'when the order has outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 123 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 123 } }
 
       it 'renders the amount as money' do
         expect(email.body).to include('$123')
@@ -149,7 +149,7 @@ describe SubscriptionMailer, type: :mailer do
     end
 
     context 'when the order has no outstanding balance' do
-      before { allow(order).to receive(:outstanding_balance) { 0 } }
+      before { allow(order).to receive(:old_outstanding_balance) { 0 } }
 
       it 'displays the payment status' do
         expect(email.body).to include(I18n.t(:email_payment_not_paid))
diff --git a/spec/models/concerns/balance_spec.rb b/spec/models/concerns/balance_spec.rb
index 331e521442..a277e46245 100644
--- a/spec/models/concerns/balance_spec.rb
+++ b/spec/models/concerns/balance_spec.rb
@@ -133,12 +133,12 @@ describe Balance do
     end
   end
 
-  context "#outstanding_balance" do
+  context "#old_outstanding_balance" do
     context 'when orders are in cart state' do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'cart') }
 
       it 'returns the order balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -146,7 +146,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'address') }
 
       it 'returns the order balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -154,7 +154,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'delivery') }
 
       it 'returns the order balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -162,7 +162,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'payment') }
 
       it 'returns the order balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -170,7 +170,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'complete') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -178,7 +178,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'complete') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -186,7 +186,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'canceled') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -194,7 +194,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'resumed') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -202,7 +202,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'payment') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -210,7 +210,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'awaiting_return') }
 
       it 'returns the customer balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -218,7 +218,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'returned') }
 
       it 'returns the balance' do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -226,7 +226,7 @@ describe Balance do
       let(:order) { build(:order, total: 100, payment_total: 10, state: 'complete') }
 
       it "returns positive" do
-        expect(order.outstanding_balance).to eq(100 - 10)
+        expect(order.old_outstanding_balance).to eq(100 - 10)
       end
     end
 
@@ -234,7 +234,7 @@ describe Balance do
       let(:order) { create(:order, total: 8.20, payment_total: 10.20, state: 'complete') }
 
       it "returns negative amount" do
-        expect(order.outstanding_balance).to eq(-2.00)
+        expect(order.old_outstanding_balance).to eq(-2.00)
       end
     end
   end
diff --git a/spec/models/order_balance_spec.rb b/spec/models/order_balance_spec.rb
index 93d5ca5d2c..a4ab2ff66d 100644
--- a/spec/models/order_balance_spec.rb
+++ b/spec/models/order_balance_spec.rb
@@ -16,7 +16,7 @@ describe OrderBalance do
 
       context 'when the balance is postive' do
         before do
-          allow(order).to receive(:outstanding_balance) { 10 }
+          allow(order).to receive(:old_outstanding_balance) { 10 }
         end
 
         it "returns 'balance due'" do
@@ -26,7 +26,7 @@ describe OrderBalance do
 
       context 'when the balance is negative' do
         before do
-          allow(order).to receive(:outstanding_balance) { -10 }
+          allow(order).to receive(:old_outstanding_balance) { -10 }
         end
 
         it "returns 'credit owed'" do
@@ -36,7 +36,7 @@ describe OrderBalance do
 
       context 'when the balance is zero' do
         before do
-          allow(order).to receive(:outstanding_balance) { 0 }
+          allow(order).to receive(:old_outstanding_balance) { 0 }
         end
 
         it "returns 'balance due'" do
@@ -86,7 +86,7 @@ describe OrderBalance do
   describe '#amount' do
     context 'when the customer_balance feature is disabled' do
       before do
-        allow(order).to receive(:outstanding_balance) { 10 }
+        allow(order).to receive(:old_outstanding_balance) { 10 }
       end
 
       before do
@@ -124,7 +124,7 @@ describe OrderBalance do
 
       context 'when the balance is zero' do
         before do
-          allow(order).to receive(:outstanding_balance) { 0 }
+          allow(order).to receive(:old_outstanding_balance) { 0 }
         end
 
         it 'returns true' do
@@ -134,7 +134,7 @@ describe OrderBalance do
 
       context 'when the balance is positive' do
         before do
-          allow(order).to receive(:outstanding_balance) { 10 }
+          allow(order).to receive(:old_outstanding_balance) { 10 }
         end
 
         it 'returns false' do
@@ -144,7 +144,7 @@ describe OrderBalance do
 
       context 'when the balance is negative' do
         before do
-          allow(order).to receive(:outstanding_balance) { -10 }
+          allow(order).to receive(:old_outstanding_balance) { -10 }
         end
 
         it 'returns false' do
@@ -199,7 +199,7 @@ describe OrderBalance do
       end
 
       it 'calls #outstanding_balance' do
-        expect(order).to receive(:outstanding_balance)
+        expect(order).to receive(:old_outstanding_balance)
         order_balance.to_f
       end
     end
@@ -216,4 +216,146 @@ describe OrderBalance do
       end
     end
   end
+
+  describe '#abs' do
+    context 'when the customer_balance feature is disabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { false }
+      end
+
+      context 'when the balance is zero' do
+        before do
+          allow(order).to receive(:old_outstanding_balance) { 0 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(0)
+        end
+      end
+
+      context 'when the balance is positive' do
+        before do
+          allow(order).to receive(:old_outstanding_balance) { 10 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(10)
+        end
+      end
+
+      context 'when the balance is negative' do
+        before do
+          allow(order).to receive(:old_outstanding_balance) { -10 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(10)
+        end
+      end
+    end
+
+    context 'when the customer_balance feature is enabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { true }
+      end
+
+      context 'when the balance is zero' do
+        before do
+          allow(order).to receive(:new_outstanding_balance) { 0 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(0)
+        end
+      end
+
+      context 'when the balance is positive' do
+        before do
+          allow(order).to receive(:new_outstanding_balance) { 10 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(10)
+        end
+      end
+
+      context 'when the balance is negative' do
+        before do
+          allow(order).to receive(:new_outstanding_balance) { -10 }
+        end
+
+        it 'returns its absolute value' do
+          expect(order_balance.abs).to eq(10)
+        end
+      end
+    end
+  end
+
+  describe '#to_s' do
+    context 'when the customer_balance feature is disabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { false }
+      end
+
+      before do
+        allow(order).to receive(:old_outstanding_balance) { 10 }
+      end
+
+      it 'returns the balance as a string' do
+        expect(order_balance.to_s).to eq('10')
+      end
+    end
+
+    context 'when the customer_balance feature is enabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { true }
+      end
+
+      before do
+        allow(order).to receive(:new_outstanding_balance) { 10 }
+      end
+
+      it 'returns the balance as a string' do
+        expect(order_balance.to_s).to eq('10')
+      end
+    end
+  end
+
+  describe '#+' do
+    let(:other_order_balance) { described_class.new(order) }
+
+    context 'when the customer_balance feature is disabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { false }
+      end
+
+      before do
+        allow(order).to receive(:old_outstanding_balance) { 10 }
+      end
+
+      it 'returns the sum of balances' do
+        expect(order_balance + other_order_balance).to eq(20.0)
+      end
+    end
+
+    context 'when the customer_balance feature is enabled' do
+      before do
+        allow(OpenFoodNetwork::FeatureToggle)
+          .to receive(:enabled?).with(:customer_balance, user) { true }
+      end
+
+      before do
+        allow(order).to receive(:new_outstanding_balance) { 10 }
+      end
+
+      it 'returns the balance as a string' do
+        expect(order_balance + other_order_balance).to eq(20.0)
+      end
+    end
+  end
 end
diff --git a/spec/models/spree/order_spec.rb b/spec/models/spree/order_spec.rb
index 5d32843056..58895613e9 100644
--- a/spec/models/spree/order_spec.rb
+++ b/spec/models/spree/order_spec.rb
@@ -310,7 +310,7 @@ describe Spree::Order do
 
   context "#display_outstanding_balance" do
     it "returns the value as a spree money" do
-      allow(order).to receive(:outstanding_balance) { 10.55 }
+      allow(order).to receive(:old_outstanding_balance) { 10.55 }
       expect(order.display_outstanding_balance).to eq Spree::Money.new(10.55)
     end
   end
diff --git a/spec/models/spree/payment_spec.rb b/spec/models/spree/payment_spec.rb
index d49898d83c..46e67ed273 100644
--- a/spec/models/spree/payment_spec.rb
+++ b/spec/models/spree/payment_spec.rb
@@ -382,7 +382,7 @@ describe Spree::Payment do
           end
 
           it "resulting payment should have correct values" do
-            allow(payment.order).to receive(:outstanding_balance) { 100 }
+            allow(payment.order).to receive(:old_outstanding_balance) { 100 }
             allow(payment).to receive(:credit_allowed) { 10 }
 
             offsetting_payment = payment.credit!
@@ -402,7 +402,7 @@ describe Spree::Payment do
             end
 
             it 'lets the new payment to be saved' do
-              allow(payment.order).to receive(:outstanding_balance) { 100 }
+              allow(payment.order).to receive(:old_outstanding_balance) { 100 }
               allow(payment).to receive(:credit_allowed) { 10 }
 
               offsetting_payment = payment.credit!
diff --git a/spec/serializers/api/order_serializer_spec.rb b/spec/serializers/api/order_serializer_spec.rb
index d635cf0ada..4d515d6c7b 100644
--- a/spec/serializers/api/order_serializer_spec.rb
+++ b/spec/serializers/api/order_serializer_spec.rb
@@ -44,12 +44,12 @@ describe Api::OrderSerializer do
       end
     end
 
-    context 'when the customer_balance is not enabled' do
+    context 'when the customer_balance is disabled' do
       before do
         allow(OpenFoodNetwork::FeatureToggle)
           .to receive(:enabled?).with(:customer_balance, order.user) { false }
 
-        allow(order).to receive(:outstanding_balance).and_return(123.0)
+        allow(order).to receive(:old_outstanding_balance).and_return(123.0)
       end
 
       it 'calls #outstanding_balance on the object' do