why is that when i charge via usb, the numeric battery shows 100% but as soon as i detach the cable it goes down to like 98%? Then I reattached the cable it goes to 95%. Stays there for a couple of minutes then go to 100%. Goes to 98% when detached again. Rinse and repeat. Is this coz my battery is not callibrated or something? I also have instances when the battery value increases while im not doing anything. For some reason the numeric value changes when the cable is detached/reattached.