Sale Order and PIR consume

Hi All ,

There is a question about sale order and PIR consume. The detail is :

en

eg, a product : FG-002 , and it's Strategy is 52 . First , key in a PIR, and qty : 80 , then receive a sale order , and qty is 100 , then , key in another PIR , and qty is 100 . based on strategy :52 's logic , SAP suggest we need only prepare 180 PCS material 。But Now , we need

prepare 200 pcs , not 180 PCS . How can we solve the problem ?