PoS UOM issue with quity field

I have issue in POS invoice with Item uom , when i add item the resulted qty = (currect qtyconversion factor )+1 …
i want it to increase by on regardless of convserion factor here is image for first and second check of item in pos the qyt increased from 1 to 13(=1
12 (convseion fator here )+1`) please advice :-1: