I'm having second thoughts about that idea. While I certainly think it's a good idea if you want to base it on a whole season's results, you wouldn't be able to do it on just a few games as the % figures would be all out of whack. You'd need a fair number of games to base it on.

Anyway, here's what I mean: Using this year's AFL Ladder, Port Adelaide had 17 wins from their 22 games. That's a winning % of 77.3%. Their for and against % was 132.4% Add 77.3 and 132.4 and you get 209.7. Then divide that by two to get their final rating of 104.85 which I rounded up to 104.9.