That doesn't factor in role change though.
Heeney is fitter than he has ever been, having had several compromised pre-seasons. Longmire said he would get more "mid" time, and he is. He is getting possessions deep in the backline. These gun players will get more ball if they get to more contests. It's the same as Cripps. The goals are cream, but they come because of the ability to go forward with a mis-match, created by being fitter and not just sitting forward all the time.
Heeney could win the brownlow if he doesn't get injured. That table above is relevant if a player is in the same role as previously, but not in this case.