I have the same issue but i think the example is incorrect.
Look at this:
If for example I’ve configured the plugin with a 2% discount on credit card payment and the VAT is 10%.
This is how the plugin must calculate correctly the taxes
Subtotal € 100,00
Discount € 2
Taxes € 9,8 (10% of the discounted subtotal)
This is how it behaves now and it’s not correct
Subtotal € 100,00
Discount € 2
Taxes €10 (10% of a the subtotal of €100)
Hope you’ll fix this soon.
Anyway thanks for your work! Is a great plugin! Keep on!
Michele