Automatic Payment Program Proposal split same vendor invoices

Hello,

We are facing some peculiar issue in Automatic Payment Program,when we run the automatic payment program payment proposal split the same vendor invoices into so many differnt proposals instead of consolidated proposal.

Every time it's not happen to same vendor it's dynamically changing to different vendors.

Eg:We have 10 vendor invoices and when we run the payment run 2 invoices is coming together and 3 invoices coming together not 10 same.

I have checked the vendor master data and payment program configuration for payment method for company code there is no tick selected for individual payment.

Could you some body explain me why system is behaving this way.

Thanks in advance.

Regards,

Satya