diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index bc44358..4fa7718 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -1249,14 +1249,14 @@
 	def update_billing_status_in_dn(self, update_modified=True):
 		updated_delivery_notes = []
 		for d in self.get("items"):
-			if d.dn_detail:
+			if d.so_detail:
+				updated_delivery_notes += update_billed_amount_based_on_so(d.so_detail, update_modified)
+			elif d.dn_detail:
 				billed_amt = frappe.db.sql("""select sum(amount) from `tabSales Invoice Item`
 					where dn_detail=%s and docstatus=1""", d.dn_detail)
 				billed_amt = billed_amt and billed_amt[0][0] or 0
 				frappe.db.set_value("Delivery Note Item", d.dn_detail, "billed_amt", billed_amt, update_modified=update_modified)
 				updated_delivery_notes.append(d.delivery_note)
-			elif d.so_detail:
-				updated_delivery_notes += update_billed_amount_based_on_so(d.so_detail, update_modified)
 
 		for dn in set(updated_delivery_notes):
 			frappe.get_doc("Delivery Note", dn).update_billing_percentage(update_modified=update_modified)