As a pretty new member who tries to look at things logically your suggestions seems to be accurate... in real life basket. This is a manager game, so my guess would be that a clutch player is the best player in the team. But I'd also assume that experience would enhance his performance in clutch situations as he's been there before, taking the team under his wings so to speak.
But being there before means that he has played enough, to regard clutch performance when distributing exp would be too complex and hard to estimate. It doesn't make sense here.