im devloping one extension to add extra fee,
but when i select paypal express checkout payment method,
it added charge to grandtotal
but when it redirect to paypal
the payment fee is not added
ill try to solve it out using
but it gives error
PayPal gateway has rejected request. The totals of the cart item amounts do not match order amounts (#10413: Transaction refused because of an invalid argument. See additional error messages for details).
We had the similar issue with iban extension and we emailed support several times with no reply so ended up using the following module.
Hope it helps!
Im not want to use any extension,
im devloping new extension of payment fee,
and issue is in that module when i payment through paypal express checkout