Invoice Verification..

Hi,

we have a problem where when we try to post an invoice with regrad to PO. We have a PO with PO amount as 1000 and Vendor has sent us an invoice for 1500 and an credit memo for 500. But when we are trying to post invoice for 1500 we cannot post it as out price variance tolerance is only 10. Could you any one let me know any way rather that changing the tolerance limits to post the invoice.

Thanks in advance

Sivaram