I just bought the newer high end 13" model in June and I noticed the battery drains pretty quickly. At most I get 4-5 hours on full charge sometimes under 4. The percentage also seems to drain pretty quickly, is this normal? I thought it was advertised as 7 hours. I did a power cycle, and it didn't seem to do much. I have only been using it for safari and iTunes, sometimes VLC. The brightness is also turned down as well, and i keep the backlight off (under the keyboard)