Iv got a 9780 and use Meterberry, iv notice that the battery shoots up to 8-10% for a short while maybe 1-2 hrs then slowly comes back down, the same happens with USB charging through the laptop.
i would say somewhat normal. during CPU intense things like installing an app, its normal to see heavier battery discharge. i usually reboot or battery pull after an install and reset the discharge rate to help it get back to normal faster.
