Bankstatement clearing not possible using Data Medium Reference

Hello

We performed a payment run for vendors, during payment run the vendors are cleared against a bank interim account, the aim is to clear this GL account automatically with the automatic bankstatement process. We have setup a correct postingrule. and the Algoritm for the external banktransaction we put to 019 DME management. We checked the DME Reference generated out of the payment run ( Data Medium ) and it is available in the bankstatement file. Now SAP dont clear the entry, saying difference to large for clearing. Now we tested with one single vendor and then SAP clears perfect ! Any idea why it dont clear

Thx