Hey, I bought my MacBook Pro about 3 months ago. It's the 2010 15" i7 model. I used iStat Pro and it's showing that my battery health is only 92% left after 18 cycles. I've tried calibrating it a few times and still stays the same. I don't understand how it just dropped suddenly this month. I'm really worried because if it stays at this rate, this battery wont last long at all. What should I do?