O paypal devolve sempre as taxas cobradas, seja qual for o método de pagamento, pelo menos para mim sempre devolveu.
Já foi assim mas já não é.
https://www.paypal.com/cgi-bin/webscr?cmd=xpt/Marketing/bizui/SendRefund-outsideIt's affordable
When you issue a full refund, your original transaction fee is credited back to you minus a thirty cent processing fee. When issuing partial refunds, a portion of the fee is returned to you.