Sometimes when I order a product, the VAT calculation comes out slightly different when I enter the data into my accounting package. Typically the difference is 1p but sometimes it is more. This seems to be due to rounding errors. Typically this happens when the supplier takes the invoice total and calculates the VAT from the invoice total in a single step at the end. My accounting package calculates VAT on a line-by-line basis then sums the VAT column.
So I end up with an invoice in my accounting system that differs from the actual suppliers invoice.
How should I cope with this situation to keep the VAT man happy? Should I enter a 1p 'correction' in my accounting system? Should I manually override the VAT amount on one of the line items? Which one?