支払手数料 is “fees paid” rather than “payment fees” - compare 支払利息 and 支払報酬. I’ve never noticed the ambiguity but your confusion is natural. I agree that it’s very

支払手数料 is “fees paid” rather than “payment fees” - compare 支払利息 and 支払報酬. I’ve never noticed the ambiguity but your confusion is natural. I agree that it’s very strange that professional services fall under 手数料 instead of 報酬, but taxes are weird in every language.