not many people know this, please read on......
VAT is calculated at the pump, to the nearest penny
when you go for £20 say, you might not be 'able' to hit that £20 due to the 'rounding up' of the VAT.
Depending on the daily price of Petrol, some days you will be able to hit it,
some days it will be impossible, as the pump will always round up to £20.01.
this is why sometimes you hit it, and sometimes you don't.
you can thank me later