After about two hours my battery on my 13" mbp is at 35% from 100%. All i did was some web browsing and about half an hour of video chatting on ichat. My brightness is at halfway. is this normal drain? the specs say 10 hours, but when i first got it it lived for about 6 hours, which was plenty for me. i've noticed recently that my battery has been acting funny, i'm thinking it may be because of my heavy audio work with garage band and reason. the app coconut battery says my battery capacity is at 94% so I'm not sure what the problem is. I've had this laptop for about 3 months, and i've properly calibrated it twice.