Third party sales - VTFA

Dear Friends,

Can someone let me know the routine to round off the quantity in VTFA (Order related billing - Third part sales). I have created a sales order with 100 LB and while billing the same the Invoice qty is showing 99.999 LBS.This is happening due to the difference in the UOM which is in KGs in Material master.

During the conversion its taking the decimals.

Thanks

Isaac