Index: modules/in-commerce/units/orders/order_calculator.php
===================================================================
--- modules/in-commerce/units/orders/order_calculator.php
+++ modules/in-commerce/units/orders/order_calculator.php
@@ -672,11 +672,11 @@
 			);
 
 			$sql = 'SELECT
-						CASE d.Type
+						ROUND(CASE d.Type
 							WHEN ' . DiscountType::FLAT . ' THEN ' . $price . ' - d.Amount
 							WHEN ' . DiscountType::PERCENT . ' THEN ' . $price . ' * (1 - d.Amount / 100)
 							ELSE ' . $price . '
-						END, d.DiscountId
+						END, 4), d.DiscountId
 					FROM ' . TABLE_PREFIX . 'Products AS p
 					LEFT JOIN ' . TABLE_PREFIX . 'ProductsDiscountItems AS di ON (di.ItemResourceId = p.ResourceId) OR (di.ItemType = ' . DiscountItemType::WHOLE_ORDER . ')
 					LEFT JOIN ' . TABLE_PREFIX . 'ProductsDiscounts AS d ON (' . implode(') AND (', $join_clause) . ')
@@ -740,11 +740,11 @@
 
 			$sql = 'SELECT
 						MIN(
-							CASE c.Type
+							ROUND(CASE c.Type
 								WHEN ' . CouponType::FLAT . ' THEN ' . $price . ' - c.Amount
 								WHEN ' . CouponType::PERCENT . ' THEN ' . $price . ' * (1 - c.Amount / 100)
 								ELSE ' . $price . '
-							END
+							END, 4)
 						)
 					FROM ' . TABLE_PREFIX . 'Products AS p
 					LEFT JOIN ' . TABLE_PREFIX . 'ProductsCouponItems AS ci ON (ci.ItemResourceId = p.ResourceId) OR (ci.ItemType = ' . CouponItemType::WHOLE_ORDER . ')