Actualy about that; If I power use like a mofo, maps, maverick, music mixing/breaking (like G-stomper), slacker streaming... essentialy on my way to a 10-18 hour battery (which is short for my norm, you've probably read other posts about this) everything will show accurate. The trick to it is if my normal medium use (the stuff that stretches me down to 10% after 40 or so hours) is not processor dependant it would make sense that it would be less than 1% of the battery used and would not show.
For an experiment, right after you pull your phone off the charger at 100% charge, enable GPS and open google maps, let it find you and follow you as you brush your teeth and get ready for work for about 10 minutes. shut down maps and disable GPS, you should (in a few minutes) see maps as 98% or so of your battery used (which will most likely be 3-5%) now as your day goes check it periodicaly and the number will shrink, in approximately 20-30 hours of no use of maps, maps will disapear from your meter and you will be left with that classic 50/50 system/dialer that we are so used to on this phone.
Just to clarify, your dialer is actualy ALOT of processes we expect from our smart phone, many of them you may think to be more appropriately system apps but their not (like sync, setting your clock, checking for/sending texts, sending/recieving E-mails, contact back-up between stupid B/U assistant google and any other such account). You will likely rarely see the screen in the usage bar due to the fact that we have a tiny low res screen, and as long as you properly close/back out of your programs they should not chew up CPU cycles.
Short answer, yes, I have looked into it extensivly, if you don't use like a MOFO (get 24+ hours on a battery from 100% to 0%) thats about what you should see. if you add "screen" to the list you have what all the super phones show with normal usage; ~20% screen ~60% system ~20%Dialer/SIM.
Good luck,
John
BTW I had a friend tell me he was worried about his battery, he "had to charge it every night when he got home from work and again in the mornings" turns out he thought 50% was dead.... He also had slacker set to auto cache 10 stations every night while the phone was unpluged... don't be that guy! Not saying you are, actualy it's kinda unrelated, just putting it out there.