I've found something that seems wrong.
We have a couple of payment methods that charge an percentage over the order, it's usually gift certificates you can buy at supermarkets, the Paysafecard in this manner.
1) Customer places a 100 euro order.
2) Want's to use a 50 euro Paysafecard (or any other)
3) There's an extra 10% costs on using that card, so instead of 50 euro's, 5 euro's are just for using it, and 45 euro's should be extracted.
4) CS Cart charges 10% over the entire ammount instead on the amount used by that card, so here 50 euro card counts as an 40 euro card.
Anyone an idea how to fix this?