I tend to watch my battery usage pretty closely, and go off time more so than the indications from the app.
The good news is that the variability seems to be in the complexity of creating a model for the multitude of CR2032 batteries and the Rechargeable.
The most predictable experience I've seen is with Energizer 2032's. I always get 12-14 hrs out of them (with the exception of 1 wonky battery). The sleep time loss is very negligible, i.e. if I don't run for a couple of days they may drop 2-3% in the app. In the end the important thing is the total run time I get.
I'm starting to look at using Energizer batteries like I do the instant MPG on the dashboard of my car. Sometimes it reads 6 which accelerating, sometimes 99 coasting down a hill. The average is pretty constant.
The rechargeable are still beta imo, and not nearly as predictable today, again imo. I've found that charging those between runs is the best course, and to be certain they stay red for a while and are actually charging.
What we're seeing, at least with a good quality CR2032 like Energizer seems to be an Indication issue, not actually Horrid Battery Life.
That's good news for us as users. No doubt the indication issues will be resolved and the rechargeable made more reliable. I'd be a lot more worried if the pods were really sucking a lot of battery when they're supposed to be asleep.