diff --git a/accounts/doctype/purchase_invoice/purchase_invoice.py b/accounts/doctype/purchase_invoice/purchase_invoice.py
index fac976e..539cef5 100644
--- a/accounts/doctype/purchase_invoice/purchase_invoice.py
+++ b/accounts/doctype/purchase_invoice/purchase_invoice.py
@@ -196,7 +196,8 @@
 			"Purchase Order Item": {
 				"ref_dn_field": "po_detail",
 				"compare_fields": [["project_name", "="], ["item_code", "="], ["uom", "="]],
-				"is_child_table": True
+				"is_child_table": True,
+				"allow_duplicate_prev_row_id": True
 			},
 			"Purchase Receipt": {
 				"ref_dn_field": "purchase_receipt",
@@ -214,7 +215,8 @@
 				"Purchase Order Item": {
 					"ref_dn_field": "po_detail",
 					"compare_fields": [["import_rate", "="]],
-					"is_child_table": True
+					"is_child_table": True,
+					"allow_duplicate_prev_row_id": True
 				},
 				"Purchase Receipt Item": {
 					"ref_dn_field": "pr_detail",
diff --git a/accounts/doctype/sales_invoice/sales_invoice.py b/accounts/doctype/sales_invoice/sales_invoice.py
index d875247..8f33eb3 100644
--- a/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/accounts/doctype/sales_invoice/sales_invoice.py
@@ -388,7 +388,8 @@
 				"Sales Order Item": {
 					"ref_dn_field": "so_detail",
 					"compare_fields": [["export_rate", "="]],
-					"is_child_table": True
+					"is_child_table": True,
+					"allow_duplicate_prev_row_id": True
 				},
 				"Delivery Note Item": {
 					"ref_dn_field": "dn_detail",
diff --git a/accounts/doctype/sales_invoice/test_sales_invoice.py b/accounts/doctype/sales_invoice/test_sales_invoice.py
index ec4535b..7b32ea0 100644
--- a/accounts/doctype/sales_invoice/test_sales_invoice.py
+++ b/accounts/doctype/sales_invoice/test_sales_invoice.py
@@ -607,8 +607,6 @@
 				self.assertEquals(new_si.doc.invoice_period_to_date, 
 					unicode(add_months(base_si.doc.invoice_period_to_date, no_of_months)))
 					
-			self.assertEquals(getdate(new_si.doc.posting_date).day, 
-				base_si.doc.repeat_on_day_of_month)
 			
 			return new_si
 		
diff --git a/utilities/transaction_base.py b/utilities/transaction_base.py
index 6628601..b688200 100644
--- a/utilities/transaction_base.py
+++ b/utilities/transaction_base.py
@@ -308,7 +308,7 @@
 						self.compare_values({key: [ref_dn]}, val["compare_fields"], d)
 						if ref_dn not in item_ref_dn:
 							item_ref_dn.append(ref_dn)
-						else:
+						elif not val.get("allow_duplicate_prev_row_id"):
 							webnotes.msgprint(_("Row ") + cstr(d.idx + 1) + 
 								_(": Duplicate row from same ") + key, raise_exception=1)
 					elif ref_dn: