Strange, my iPhone 4 would stay on 100% for like 15-20 minutes of use, I suspect it was a software thing to make it look like it was such a good battery because it always drained faster below 99% than it did going from 100% to 99%.
Problem is, you'll never know. So you're basing your desires off of an incorrect assumption that this number is exact....when its not. This number, into itself, is merely a guess.
I would also obsessively watch the number if I keep it on my status bar. But, I don't like how far buried it is in the settings menu to see it when I want to check. So, I stuck the battery center widget on my notification center drop down (via jailbreak) so I can check with a simple down swipe. Best compromise for me.
I only have it on my iPad mini. Turned off on my 4S. I hated it because I was constantly glancing at it, and without it on, it gives me more peace of mind, even if it's false.
Recently turned it off on my 5. I think it's off by default anyway. But I don't need to see every percent that I lose. The phone'll notify me via the 20% popup when I need to charge.