My iPhone 4s started to show Usage & Standby as the same. So I called Apple Care (Friday 27th Jan) and told them this can't possibly correct, they said "Ah, this is a known anomaly", go to Settings, General, About then scroll down to Version. If you see Version as 5.0.1 (9A405) then you need to do a (Restore With Update").
After following their instructions, iPhone now displays Version as 5.0.1 (9A406) Plus Usage & Standby is now displaying correctly with battery at 71% Usage 2 Hours 17 Minutes Standby 14 Hours, 0 Minutes.
After following their instructions, iPhone now displays Version as 5.0.1 (9A406) Plus Usage & Standby is now displaying correctly with battery at 71% Usage 2 Hours 17 Minutes Standby 14 Hours, 0 Minutes.