Fluctuating maximum battery capacity I've noticed today that my MBP 15" late 2014 maximum battery capacity is fluctuating somewhat.

These two screenshots were taken just seconds apart http://imgur.com/a/jqyZs

Should I be worried? Should I "recalibrate" the batteries?

Thanks!
The system management controller is responsible for reading battery voltages and reporting it to the operating system. You could reset that one time to see if it made a difference. When the output voltage of the battery shifts like that, it's a sign of failure within the battery. 

Getting the machine serviced would be the way to fix that if it's not the SMC.