This is why you won’t see the average tier term in the final equation, although the information from which tiers were played is in the methodology, in the earlier steps.
So part of the information in WN8 now includes both the tanks a player has chosen, but also the number of games played on an account.
So in WN8 we’ve adopted an entirely different method. Noobmeter’s Performance Rating has used a per-tank rating since its inception, and while PR was initially skeptically received because the formula was closed source, Mr.
Noobmeter released it months ago and explained its formulation.
Some of these were known at the time of release of WN7 and others were discovered and publicized shortly thereafter.