v5.0.3 fixes are listed as follows:
Fixed Battery time remain problem with random life appearing in certain rare cases
Improved how Battery time remain is calculated
Fixed problem with Notes / Word not closing / opening correctly through Power Task
Fixed problem with some apps not reactivating correctly when using Power Task
Fixed problem when occasionally alerts wouldn't sound after a power on event
...I just loaded it and the time remaining no longer fluctuates
I have a fully charged battery and it's initially showing 1h 54m r.
Let's see how/if over the next few days of use, the time remaining display steadily gets more and more accurate.
I may be an optimist, but I think this time they finally fixed it !