Interesting. I don't see why they just can't give every game home and away individual loyalty points and just use a rolling 3 seasons. Obviously need to factor in ST and could do on a diminishing basis i.e. Points accumulated from last season gets reduced by say 40% going into the following season. Straightforward to have a cumulative total against each membership. A bloody spreadsheet could do it!
In addition could also let 'uber fans' brag about their score.