diff --git a/models/sale_order.py b/models/sale_order.py
index 29b070c50c1..d88d8cfc3d9 100644
--- a/models/sale_order.py
+++ b/models/sale_order.py
@@ -111,7 +111,8 @@ class SaleOrder(models.Model):
             return fixed_amount
 
     def _get_lines_unit_prices(self):
-        return [x.price_unit for x in self.order_line.filtered(lambda x: not x.is_reward_line)]
+        # Unit prices tax included
+        return [x.price_total / x.product_uom_qty for x in self.order_line.filtered(lambda x: not x.is_reward_line)]
 
     def _get_reward_values_discount_percentage(self, program):
         discount_amount = 0
@@ -123,7 +124,7 @@ class SaleOrder(models.Model):
             unit_prices = self._get_lines_unit_prices()
             discount_amount = (min(unit_prices) * (program.discount_percentage) / 100)
         if program.discount_apply_on == 'specific_product':
-            discount_amount = sum([(x.price_total * x.product_uom_qty) * (program.discount_percentage / 100) for x in self.order_line.filtered(
+            discount_amount = sum([x.price_total * (program.discount_percentage / 100) for x in self.order_line.filtered(
                 lambda x: x.product_id == program.discount_specific_product_id)])
         if program.discount_max_amount and discount_amount > max_amount:
             discount_amount = max_amount
diff --git a/tests/test_program_numbers.py b/tests/test_program_numbers.py
index fcb5002d5c0..9a698f3cf9b 100644
--- a/tests/test_program_numbers.py
+++ b/tests/test_program_numbers.py
@@ -178,3 +178,11 @@ class TestSaleCouponProgramNumbers(TestSaleCouponCommon):
         order.recompute_coupon_lines()
         # (10x25) + (320 +15% tax) - (20% of (320 + 15% tax) = 250 + 368 - 73.6 = 544.4
         self.assertEqual(order.amount_total, 544.4, "We should only get reduction on ipad")
+        sol1.product_uom_qty = 10
+        order.recompute_coupon_lines()
+        # (10x25) + (10x (320 +15% tax)) - (20% of (10x (320 + 15% tax))) - 2 free iPads = 250 + 3680 - 736 - 736 = 2458
+        self.assertEqual(order.amount_total, 2458, "Changing ipad quantity should change discount amount correctly")
+
+        p_specific_product.discount_max_amount = 200
+        order.recompute_coupon_lines()
+        self.assertEqual(order.amount_total, 2994, "The discount should be limited to $200")