you are plainly wrong and have never filled in a tax return
your words,
you paid $42.00 for petrol and chocolate
you did it twice, so you paid $4.00 total for chocolate
you got $3.00 back from the chocolates
you cant write off the chocolates that you got for free, the tax system just wont allow it
$4.00 less $3.00 means you are out of pocket
it's that simple
