Hmm yea, I know that they break players down % for their ease, e.g. 40% SF, 40% SG, etc. I think they have moved to using only this years data, still seems odd that some of them are vastly different.
Maybe I'll look at it more. The most blatant example today is Vucevic. They have it as an extremely low matchup ease, where FC has it as a very positive dvp.