With the Amon Ra recovery, reboot to recovery, choose the wipe option, then wipe battery stats. Best to do when the battery is fully charged.
I feel you on the Otterbox part. I love my Commuter version as much as I love my phone. It's a fantastic case.
But you gotta shut of 4G when you're not browsing, man. There's a toggle widget for it under HTC widgets. Just give it a shot for a while and see how it goes.
I realize back on 3G phones that we never had to shut off data, but now your phone is going through twice the power consumption on seeking out and maintaining both 3G and 4G signals.