Here is the fix for your battery stat problem
You have to re-calibrate your battery. My wife and I own galaxy s2. I am on ics 4.0.3, rooted but stock firmware and my wife's phone is on gingerbread, rooted but stock 2.3.3 . I think this will work regardless of your phone being rooted or not. This will re-calibrate your battery. Your problems happen when the phone operating system thinks the battery is 100% charged when physically phone battery is only 60%. Or vise versa when physical phone batter is 100% and operating system thinks its 60% (or what ever value). Hope this fixes all your battery problems. Dont worry, this happened to my phone and my wife's phone and all is well. Your welcome.
1) drain all of your battery untill phone shuts down
2) turn on and drain battery until phone shuts down ( repeat until you are unable to turn the phone on- this step is very important because we need to drain the battery competely)
3) take the battery out and wait 5 seconds or so and put it back in
4) Charge the battery while the phone is off
5) when the charge is 100%, take the charger off then charge again to get 100% again
6) turn on your phone and enjoy your new battery