rework order issue

Dear experts

I am doing rework order process through Co01 with order type Ybw1(rework ordert ype) for semifinished prodcut, I created prodcuion order, and created Reference operaion set and I did goods issue against for that partiacular production orde. Now,

I am doing CO11N (confirmation) here am entering producion order number, in the yeild quantity 266 is coming but I created prodcuion order qty is only for 80. what is the problem ? The same thing I observed in Prodcution order Operaion overview also

when I am changing qty in production order qty in operaion overview the qty is changing. how can i solve this problem. After in co11n when I click the goods movement the quanity is 79. what is the problem? why such differences in qtys?

I want prodcuion order quantity as same in yeild quanity in co11n also in co11n goods movement qty.

raz