Do you do this on a regular basis (eg once a week perhaps), or just when you upgrade firmware/rom/kernel etc. or perhaps when you restore from CWM as i assume the file the battery calibration app wipes gets restored in a CWM restore, so upon restoring, the data in this file would differ from the actual physical properties of the battery. Or is it just not necessary? Also, there is a "wipe battery stats" (or similar) in CWM Advanced menu. Is this different to running the battery calibration app? If so, what does this do?