diff --git a/erpnext/controllers/accounts_controller.py b/erpnext/controllers/accounts_controller.py
index 0198d5f76e5..66a3dd93169 100644
--- a/erpnext/controllers/accounts_controller.py
+++ b/erpnext/controllers/accounts_controller.py
@@ -4060,6 +4060,7 @@ def update_child_qty_rate(parent_doctype, trans_items, parent_doctype_name, chil
 
 	parent.set_payment_schedule()
 	if parent_doctype == "Purchase Order":
+		parent.set_tax_withholding()
 		parent.validate_minimum_order_qty()
 		parent.validate_budget()
 		if parent.is_against_so():