I've noticed that my battery meters are doing some strange things and could use some calibration. 1. On the draining from 100% to 10% step, does it matter if you turn the device off in during this. I prefer to turn my devices off at night, and this would be a multi-day process for me (especially on my Nexus 7, I could easily take 3 or 4 days on this step alone). Should I leave my devices on overnight during this process. 2. During charging, you recommend using the wall charger with the device off. Actually this applies to charging all the time, not just calibration - but is this just for speed, or is it preferable? Is using the wall charger better than plugging the usb into the computer? Is leaving the device off while charging better than leaving it on?