Purchase account management is not working for subcontracting PO

Dear All

I have activated the purchase account management and 2 new entries get updated in MIGO in case of standard PO as below and this ok.

Debit - Purchase Account  (EIN)

Credit- Purchase offsetting account (EKG)

But in case of subcontracting PO, it is not working.can anybody explain why this is happening?

Thanks and Regards

Rajesh