my macbook battery's capacity is 5341 mAh. the original was 5020. is this the charger's problem or is it the batteries?
( i get my battery info from coconut battery.)
Most MacBooks I've seen will report more mAh than the battery is rated for. You're fine.
I figure Apple lists a given mAh rating as the minimum that a battery will be able to hold when new, but it's not uncommon for the figure to be higher. It's their way of making sure people don't come back complaining when their new battery is 15mAh under the rated amount...at least that's what I think.
I think a regular battery calibration - full charge > full discharge > full charge - also increases the capacity. Most rechargeable batteries need several full charge/discharge cycles to reach optimum capacity.