invoices creating addition balance due

Hi All,

We have a strange problem during invoice posting into accounting. These invoices are paid through credit card. ( Std. SAP credit card configuration is done. Authorization takes place in the sales order by interaction with an external system.). In the invoice sometime billing value ( this filed exists in Header->Payment Card screen) is getting populated less than the net value of the invoice. Authorized amount is coming sufficient to satisfy the net value. This is causing the balance due in accounting document.

Any help is much appreciated

Regards,

Subhankar