diff --git a/erpnext/controllers/buying_controller.py b/erpnext/controllers/buying_controller.py
index 3a802bd..ece08d8 100644
--- a/erpnext/controllers/buying_controller.py
+++ b/erpnext/controllers/buying_controller.py
@@ -105,26 +105,26 @@
 	def set_rate_for_standalone_debit_note(self):
 		if self.get("is_return") and self.get("update_stock") and not self.return_against:
 			for row in self.items:
+				if row.rate <= 0:
+					# override the rate with valuation rate
+					row.rate = get_incoming_rate(
+						{
+							"item_code": row.item_code,
+							"warehouse": row.warehouse,
+							"posting_date": self.get("posting_date"),
+							"posting_time": self.get("posting_time"),
+							"qty": row.qty,
+							"serial_and_batch_bundle": row.get("serial_and_batch_bundle"),
+							"company": self.company,
+							"voucher_type": self.doctype,
+							"voucher_no": self.name,
+						},
+						raise_error_if_no_rate=False,
+					)
 
-				# override the rate with valuation rate
-				row.rate = get_incoming_rate(
-					{
-						"item_code": row.item_code,
-						"warehouse": row.warehouse,
-						"posting_date": self.get("posting_date"),
-						"posting_time": self.get("posting_time"),
-						"qty": row.qty,
-						"serial_and_batch_bundle": row.get("serial_and_batch_bundle"),
-						"company": self.company,
-						"voucher_type": self.doctype,
-						"voucher_no": self.name,
-					},
-					raise_error_if_no_rate=False,
-				)
-
-				row.discount_percentage = 0.0
-				row.discount_amount = 0.0
-				row.margin_rate_or_amount = 0.0
+					row.discount_percentage = 0.0
+					row.discount_amount = 0.0
+					row.margin_rate_or_amount = 0.0
 
 	def set_missing_values(self, for_validate=False):
 		super(BuyingController, self).set_missing_values(for_validate)