Give exact calculation. Thing is that you have interexchange fees that mastercard takes that they don't write in their TOS (actually they do, it's just convoluted). so you have their fee + percentage + mastercard exchange fee. You can speak to their live chat and they will explain.
What you do is this.
Go on
https://www.mastercard.us/en-us/cons...-currency.html. Type in the currency you have and what you are converting it to on exact date the settlement is shown in firstchoicepay. Then take out i think it's 3.5% of that for mastercard exchange fee. Then apply firstchoice fees.