Hello, I would like to ask you somethings. 8-9 months ago I bought the macbook pro 13' 2011. Some months after buying it I noticed maximum charge decreased, even after calibrating it. Now it marks a 92 % of design capacity. I have some mates who also have mac that their autonomy is greater than mine, being able to use they mac 7-8 hours whereas I only can use 5-6. I heard rumors saying that many batteries of mac boor pro 2011 are defective. Do you think is that true and maybe my battery is defective? Using 50-60 % of brightness and using chrome I can use Mac about 5 hours. Do you think my time of use is right? Thanks!