A problem in J3AT AFS

Dear Experts,

I have a problem in J3AT AFS. for example: SO1 is 10 PCs, SO 2 is 100 PCs. the inventory is 100 PCs.

After i had done J3AT for SO1, the available inventory = 100 - 10 = 90 PCs. but when i did J3AT  fot SO2, the availabel qty is 100 PCs , The available qty should be 90 PCs for SO2. how to fix the problem?

thanks in advance.

Coliin