Yeah, I believe you are right - that the stepdown is still there, but is barely noticeable. I read somewhere (included manual?) that the light makes multiple gradual steps down from high after the 3 minute timer. I also think that the max output you get from High is dropping so fast because of the high current draw from the battery (and in my case probably dropping faster than other cells). So in other words, you’re not hitting that “2500” lumen level after you’ve used the light a few minutes - so when you click back up to high after some stepdown you may only jump back up to say 1600 lumens. I’d like to do some testing of this “high runtime” and am thinking to rig up a DMM measuring tailcap current while the light runs in my DIY sphere with a timer running and my action cam running timelapse. Of course the test will really only be accurate for anyone else running the same cell. I believe high mode is really only usable for just a few minutes from start and that this is mainly a medium/low mode light. They probably should have just made modes Low-Med-High-Turbo and noted that Turbo was only usable for a few minutes on a fresh cell. Anyway, I was counting on using Medium mode for MTB riding anyway - a nice regulated 900 lumens for 2.5 hours.
Last night on my fully charged 50E I was seeing high mode hold at +/- 7.5A for about 15 seconds (that’s as long as I tested it) and not just immediately drop to medium level, so I know the last test was due to the battery level.
-Garry