1. The odds need to be set properly. The mirror match should have odds, not be a fixed outcome. I'll repeat again - if you do it the way it's written now, then (following the exploit due to the flawed formula for small maps and G+U) there will also be an exploit with small mirror matches. 2. Having full statistics on hand, there's no particular reason to reset everything. Yes, the result for a specific date should be recorded. But what prevents simply recalculating the rating using the new formula from the beginning of time and making this the new rating immediately? If a safety net is needed, you can reduce all results by 2 during the recalculation.