DZ Document Showing Future Baseline Date

We have a DZ document that is showing a future baseline date. The billing document was created 12/14/09 and payment document was generated 12/28/09. The payment terms in OBB8 is net due 55days. However the baseline date in the clearing document is showing 02/07/10. I thought Baseline date is the starting date the system uses to calculate the invoice due date, standard SAP?

Any idea why this is happening?

Regards,

Keen