diff --git a/app/models/spree/calculator/per_item_decorator.rb b/app/models/spree/calculator/per_item_decorator.rb
index 1c5369b48a..e385ad8bf8 100644
--- a/app/models/spree/calculator/per_item_decorator.rb
+++ b/app/models/spree/calculator/per_item_decorator.rb
@@ -13,14 +13,15 @@ module Spree
     def compute(object = nil)
       return 0 if object.nil?
 
-      preferred_amount * line_items_for(object).reduce(0) do |sum, value|
-        value_to_add = if matching_products.blank? || matching_products.include?(value.product)
-                         value.quantity
+      number_of_line_items = line_items_for(object).reduce(0) do |sum, line_item|
+        value_to_add = if matching_products.blank? || matching_products.include?(line_item.product)
+                         line_item.quantity
                        else
                          0
                        end
         sum + value_to_add
       end
+      preferred_amount * number_of_line_items
     end
   end
 end