My device has been plugged in all night because it took hours to finish downloading the update so during installation, my phone was at 100% until I unplugged the charger. I then tinkered with it for "few" minutes then left the phone on my desk still at 100%. Bluetooth and WiFi were turned off. Background refresh, push email and location services were likewise turned off. 2 hours thereafter, I checked my phone and the battery dropped 4%. I went to battery settings and I noticed that the battery usage and the battery standby were the same (1h 46m) which is weird because I didn't use my phone that long after unplugging it from the charger. I observed that the battery standby and the battery usage are exactly the same NO MATTER WHAT.