SAP Outbound delivery qty is split

Hi ,

1. i created PR , and under delivery address tab i kept vendor number and marked check box  SC Vendor.

2. PR with Materaial A and qty 100 and delivery date 10.05.2016

3. Run ME2O transaction and pulled my PR and created outbound delivery

Now surprise is

Outbound delivery is having 2 line items ( Material A is repeated) and qty for line items are 56 and 34 respectively

Now question is Why qty 100 is split into 2 line items as 56 and 34.

Would you please suggest any idea.

Regards

Ramakrishnaiah Y