Error while posting confirmation from SRM

Hello ,

We are getting error message - Quantity exceeds remaining balance of POwhile posting confirmation from SRM though the entered quantity is well

within outstanding quantity.

The PO in question is Service PO with 11 line items created from SRM. For the first 5 line items we are to post confirmation from SRM. But for the remaining we get this error while posting conformation.

Any inputs for investigation .....

Thanks & Regards,

Pankaj