Payment Document Numbers and Voucher Numbers are going in ZIGZAG(Not in same phase) in Payment Batch

Hi All, 

We recently upgraded to 11.10.2 from 11.9 

Usually the Payment document numbers and voucher numbers will be in the same phase with increasing but in our case they are getting mapped in zigzag order


Ex: Doc No    Voucher NO
2501927         689168
2501928         689169
2501929         689170
2501821         689171
2501822         689172
2501823         689173...like wise

we came to know about this after running the final payment register report output. Before we upgrade we used to have these number going in order now it is not fallowing

Is there any way to make them fallow in the same order any suggestions would by greatly appreciated.

Regards,

Dasthagiri.