3G S - 'Time since last full charge" counter wrong?

[k-sherms]

Ever since i got my 3G S a week ago, the counter for 'time since last full charge' has been way off. Today, despite only having the phone off the charger for 12 hours, the counter read:
5 hours 56 minutes usage, and 14 hours 55 minutes standby
that equals almost 21 hours of time, when it's been only 12 hours off the charger!
the battery was at 20%
This has been normal for me since i got the phone. i have tried restoring, setting up from a backup of my old 3G, restoring again, setting up as a new iPhone, draining the battery all the way, then fully charging it to callibrate, all with no luck.
This has become very frustrating because i feel like i am not getting proper battery life, yet i have no way to for sure know. can someone please point me in the right direction, as to how to solve this? thanks

 

[straleno]

Well, one thing I can tell you is that usage time is INCLUDED in standby time, not in addition to it.

 

[k-sherms]

that still puts the total time 3 hours more than the actual time it's been off the charger. any idea what could be causing this? thanks for the response.