Requisition total does not equal autocreated PO

 Hi Gurus,

We have a requisition with three lines totaling $49300

Qty   Price   Total

4      6300    25200

1      11500  11500

2      6300    12600

                    ---------

                    49300

When the PO was auto created number of lines created are 2 with total quantity of 7. But the total amount is $44100 only. which is a difference of $5200. System created the PO in the following way

Qty   Price   Total

5      6300    31500

2      6300    12600

                    ---------

                    44100

Can anyone let me know why this would have happened? There was no manual update on the PO.

Thanks,

Srikanth