More fun with charts; here's what I see for 4th bar drop by model year for Ahr & Hx. I only included ones for which I could find the forum post, not everything on the

wiki. Clearly the 2013s behave differently, with the 4th bar drop at lower Ahr & higher Hx... There are a few weird outlier numbers, too. In particular

co2112's numbers seem pretty far out of the normal range.

Google sheet is here(Edit: Updated with a few more entries I found. Far more 2011s than 2012, though perhaps that's expected simply due to age. 2012s have a wider range on Ahr. Come on 2012's, show me what you've got!)

(Last update: Removed co2112's outlier numbers, they were drop to 9th bar not drop of 9th bar, AFAICT; added a few more stats I found)