Thanks for putting the battle tier into the battle results file. I rand some stats based on the MM leve (e.g. MaxBattleTier-TankTier) to see how my tanks' WR varied with the tier. It was interesting to see how some tanks performed fine in higher tier battles and some were far more effective when top tiers (typically derp tanks like the Jumbo).
However there is a limited amount of data with one player and it may well be work running some global statistics on this to show how each tank does on average with 0, +1, +2.