that there was no over achievement based on facts
Wins Scores value as a projector is not a "fact", and it's agreement in where the Sixers finished is not proof of accuracy.
Derived stats such as this are interesting, compelling, and at times can be used as supportive evidence. But the limit of stats being "facts" is saying that somebody did, indeed, pull down 8.5 rebounds per game. Their use as a projector is not factually proven.