diff --git a/classes/Carrier.php b/classes/Carrier.php
index 130aebd85..6de5899aa 100644
--- a/classes/Carrier.php
+++ b/classes/Carrier.php
@@ -775,11 +775,11 @@ class CarrierCore extends ObjectModel
 			if ($delete)
 				Db::getInstance()->execute('
 					DELETE FROM `'._DB_PREFIX_.'delivery` 
-					WHERE id_shop = '.(int)$values['id_shop'].' 
-					AND id_shop_group='.(int)$values['id_shop_group'].' 
+					WHERE '.(is_null($values['id_shop']) ? 'ISNULL(`id_shop`) ' : 'id_shop = '.(int)$values['id_shop']).' 
+					AND '.(is_null($values['id_shop_group']) ? 'ISNULL(`id_shop`) ' : 'id_shop_group='.(int)$values['id_shop_group']).'
 					AND id_carrier='.(int)$values['id_carrier'].
-					($values['id_range_price'] !== null ? ' AND id_range_price='.(int)$values['id_range_price'] : '').
-					($values['id_range_weight'] !== null ? ' AND id_range_weight='.(int)$values['id_range_weight'] : '').'
+					($values['id_range_price'] !== null ? ' AND id_range_price='.(int)$values['id_range_price'] : ' AND (ISNULL(`id_range_price`) OR `id_range_price` = 0)').
+					($values['id_range_weight'] !== null ? ' AND id_range_weight='.(int)$values['id_range_weight'] : ' AND (ISNULL(`id_range_weight`) OR `id_range_weight` = 0)').'
 					AND id_zone='.(int)$values['id_zone']
 				);