Intenal order budget utilized value remove after GRN

Dear Expert

I have a question regarding asset budget check , using internal order in PO.

I have create the statistical internal order and maintain budget in the Internal Order.

During the Purchase Order entry, I have enter the asset master /GL Account/ Co center...system should utilized budget against the internal order

e.g. Internal order against budget value 100000 L and PO order value 50000 K

system showing in report budget value 100000 L committed value 50000 and available more 50000 

but when I do the Good receipt system automatically remove committed value and available again more of 100000 L

I did not understand why this is happen could any one helping and give the solution

Thx

Sachin v