Im looking at the Acebeam L30 and its runtime at 4000 lumens is “2 mins + 1 hour”
Does this mean it should run for 1 hour and 2 minutes?
It’s most likely 4000 lumens for 2 minutes and then it will step down and continuing running for an hour.
Bah, beat me to it. 
Yeah, here ya go…
High: 2000 lms, 1.1 hours
Turbo: 4000 lms, 2 mins + 1 hour
So it probably steps down after 2min at 4000lm and burns the rest of the way at 2000lm.
So that 2min burn on turbo ate up 0.1hr worth of high.