Assembly Scrap

I am maintaing assembly scrap % for an assembly.Whenever I am Creating Order It increases order qty based on assembly % maintained in material master.But at the time of GR also once again it incraeses qty for assembly scrap %.How to solve this issue.

Eg:

Order Qty : 100

Assembly Scrap %: 10

Chnaged Order Qty : 110

GR propoded Qty : 121