diff --git a/erpnext/manufacturing/doctype/work_order/work_order.py b/erpnext/manufacturing/doctype/work_order/work_order.py
index 03e0910..b4e489a 100644
--- a/erpnext/manufacturing/doctype/work_order/work_order.py
+++ b/erpnext/manufacturing/doctype/work_order/work_order.py
@@ -449,7 +449,13 @@
 
 	def update_ordered_qty(self):
 		if self.production_plan and self.production_plan_item:
-			qty = self.qty if self.docstatus == 1 else 0
+			qty = frappe.get_value("Production Plan Item", self.production_plan_item, "ordered_qty")
+
+			if self.docstatus == 1:
+				qty += self.qty
+			elif self.docstatus == 2:
+				qty -= self.qty
+
 			frappe.db.set_value('Production Plan Item',
 				self.production_plan_item, 'ordered_qty', qty)