I see top as meaning "insertive", either in the mouth or ass. I see bottom as meaning "receptive", again either ass or mouth. Thus an oral top is a guy who wants to stick his dick in >your< mouth. An oral bottom is a guy who wants your dick stuck in >his< mouth. Anal top, he fucks you. Anal bottom, you fuck him. Then there is versatile, like me, who likes it all
As for "with benefits", I don't see that as meaning compensaiton. At least around here, it just means two guys who want to get off with each other...... who want more than just a friend... a mutual benifit. Maybe the definition is regional.