diff --git a/models/sale_order.py b/models/sale_order.py
index e0f91648823..0d11cd8c159 100644
--- a/models/sale_order.py
+++ b/models/sale_order.py
@@ -13,14 +13,14 @@ class SaleOrder(models.Model):
         lines = self.order_line.filtered(lambda line: line.is_delivery or line.product_id in free_delivery_product)
         return lines + super(SaleOrder, self)._get_no_effect_on_threshold_lines()
 
-    def _get_order_lines_tax_included_amount(self):
+    def _get_paid_order_lines(self):
         """ Returns the taxes included sale order total amount without the rewards amount"""
         free_reward_product = self.env['sale.coupon.program'].search([('reward_type', '=', 'product')]).mapped('discount_line_product_id')
-        return sum([x.price_total for x in self.order_line.filtered(lambda x: not (x.is_reward_line or x.is_delivery) or x.product_id in free_reward_product)])
+        return self.order_line.filtered(lambda x: not (x.is_reward_line or x.is_delivery) or x.product_id in free_reward_product)
 
     def _get_reward_line_values(self, program):
         if program.reward_type == 'free_shipping':
-            return self._get_reward_values_free_shipping(program)
+            return [self._get_reward_values_free_shipping(program)]
         else:
             return super(SaleOrder, self)._get_reward_line_values(program)
 
@@ -40,9 +40,9 @@ class SaleOrder(models.Model):
             'tax_id': [(4, tax.id, False) for tax in taxes],
         }
 
-    def _get_lines_unit_prices(self):
+    def _get_cheapest_line(self):
         # Unit prices tax included
-        return [x.price_total / x.product_uom_qty for x in self.order_line.filtered(lambda x: not x.is_delivery and not x.is_reward_line)]
+        return min(self.order_line.filtered(lambda x: not x.is_reward_line and not x.is_delivery and x.price_unit > 0), key=lambda x: x['price_unit'])
 
 class SalesOrderLine(models.Model):
     _inherit = "sale.order.line"
diff --git a/tests/test_free_shipping_reward.py b/tests/test_free_shipping_reward.py
index 5c8cce3d1a4..175a06d0c76 100644
--- a/tests/test_free_shipping_reward.py
+++ b/tests/test_free_shipping_reward.py
@@ -120,6 +120,9 @@ class TestSaleCouponProgramRules(TestSaleCouponCommon):
         self.assertEqual(len(order.order_line.ids), 3, "We should get the delivery line but not the free delivery since we are below 872.73$ with the 10% discount")
 
         p_minimum_threshold_free_delivery.sequence = 10
+        (order.order_line - sol1).unlink()
+        order.carrier_id = self.env['delivery.carrier'].search([])[1]
+        order.delivery_set()
         order.recompute_coupon_lines()
         self.assertEqual(len(order.order_line.ids), 4, "We should get both promotion line since the free delivery will be applied first and won't change the SO total")
 
@@ -193,5 +196,5 @@ class TestSaleCouponProgramRules(TestSaleCouponCommon):
         })
         p_specific_product.discount_apply_on = 'cheapest_product'
         order.recompute_coupon_lines()
-        # 872.73 - (20% of 1 iPad) = 872.73 - 64 = 808.73
-        self.assertEqual(order.amount_untaxed, 808.73, "One iPad should be discounted by 20%")
+        # 872.73 - (20% of 1 iPad) = 872.73 - 58.18 = 814.55
+        self.assertEqual(order.amount_untaxed, 814.55, "One iPad should be discounted by 20%")