diff --git a/app/assets/javascripts/darkswarm/controllers/shop_variant_controller.js.coffee b/app/assets/javascripts/darkswarm/controllers/shop_variant_controller.js.coffee
index 825bc9f39f..e71a7a0a29 100644
--- a/app/assets/javascripts/darkswarm/controllers/shop_variant_controller.js.coffee
+++ b/app/assets/javascripts/darkswarm/controllers/shop_variant_controller.js.coffee
@@ -1,9 +1,5 @@
 Darkswarm.controller "ShopVariantCtrl", ($scope, $modal, Cart) ->
-  $scope.$watchGroup [
-    'variant.line_item.quantity',
-    'variant.line_item.max_quantity'
-  ], (new_value, old_value) ->
-    return if old_value[0] == null && new_value[0] == null
+  $scope.updateCart = (line_item) ->
     Cart.adjust($scope.variant.line_item)
 
   $scope.variant.line_item.quantity ||= 0
@@ -44,10 +40,12 @@ Darkswarm.controller "ShopVariantCtrl", ($scope, $modal, Cart) ->
   $scope.add = (quantity) ->
     item = $scope.variant.line_item
     item.quantity = $scope.sanitizedQuantity() + quantity
+    $scope.updateCart(item)
 
   $scope.addMax = (quantity) ->
     item = $scope.variant.line_item
     item.max_quantity = $scope.sanitizedMaxQuantity() + quantity
+    $scope.updateCart(item)
 
   $scope.canAdd = (quantity) ->
     wantedQuantity = $scope.sanitizedQuantity() + quantity
diff --git a/spec/javascripts/unit/darkswarm/controllers/checkout/shop_variant_controller_spec.js.coffee b/spec/javascripts/unit/darkswarm/controllers/checkout/shop_variant_controller_spec.js.coffee
index 4576e376c7..c560a287c4 100644
--- a/spec/javascripts/unit/darkswarm/controllers/checkout/shop_variant_controller_spec.js.coffee
+++ b/spec/javascripts/unit/darkswarm/controllers/checkout/shop_variant_controller_spec.js.coffee
@@ -1,6 +1,7 @@
 describe "ShopVariantCtrl", ->
   ctrl = null
   scope = null
+  CartMock = null
 
   beforeEach ->
     module 'Darkswarm'
@@ -16,7 +17,10 @@ describe "ShopVariantCtrl", ->
           max_quantity: undefined
         }
       }
-      ctrl = $controller 'ShopVariantCtrl', {$scope: scope, $modal: $modal, Cart: null}
+      CartMock =
+        adjust: ->
+          true
+      ctrl = $controller 'ShopVariantCtrl', {$scope: scope, $modal: $modal, Cart: CartMock}
 
   it "initializes the quantity for shop display", ->
     expect(scope.variant.line_item.quantity).toEqual 0