The ICE has poor mpg when warming up, so my thought is that SAVE cycles the ICE on/off/on/off, so not that efficient.
I prefer to run EV to 5 miles left, then CHRG up to say 15 miles range, then run EV again, etc.
But I also try to use EV in town and B roads, and CHRG at 50 to 60 mph on A...