think of the PI as a "batting average". If you win every race, you have an index of 1000. It's a multiplier. if you win a race, 35 points, get multiplied by 1.00 since your index is 1000. If your index is 500, from finishing middle of the pace on average, your multiplier is .5 so your 35 points are multiplied by .5 thus you don't have 35 points, you have 17.5 points. The multiplier adjusts every race weekend. Win a race, then finish mid pack, you have an index of 750. (or a multiplier of .75).

Now, that is for each class. the OVERALL index is the average of ALL your races. If i understand correctly, it USED to be the average of each class. Win every race ALL SEASON LONG, pi of 1000.. but did scatty in ONE RACE IN ONE CLASS (250 performance index).. your overall index, even though you won 9 races in one class, and finished nearly last 1 time in one class.. is still 625 for your overall. That kind of sucked. And, it discouraged riders from every doing a 1 off race just to have fun, for fear of wrecking the overall PI. Now, the overall is just that.. the PI of ALL your races.

The PI is simply a multiplier rewarding good "performance". Especially when some classes have few riders. 5th place points are still pretty good, but when you finish 5th out of 5 consistently, you have a very low PI, and that multiplied by 5th place points results in VERY FEW points :)

hows that ??