Payment Method issue

Hi SAP gurus,

Payment method is maintained in the customer master (company code data). We enter a value so that it will be copied as a default upon order entry.

However, there are certain cases that upon order creation, a different payment method is being defaulted to customers. For example, customer1 has payment method 'A' (cheque) maintained in XD03. Sometimes, the payment method defaulted in customer1s order is not 'A'. This happens in about 20 out of 100.

I'm wondering, is there any other configuration or possible set-up that is over riding the payment method assigned in XD03? The user said he did not change this field (VBKD-ZLSCH) upon order creation. I did replicate the orders with issues but the payment method is correctly pulled from the customer master.

Please, could you help me on this one?

Thank you very much!

Olyn