Late to this thread... I have a 2013 MBA which is at 790 cycles, 78%, and battery condition is still GOOD. Still getting 6-7 hours of life out of it.
The % figure fluctuates some, and, at one point, I got warnings that the battery was in a REPLACE state. However, I ran the laptop down all the way, plugged it in for several hours WITHOUT using it, and it came back fine.
The other day, I ran it down inadvertently for the first time in months, and it came back at 81%! The battery life jumped back to about 8-9 hours (reported, not fully tested).
Somewhere it was reported that it's good to keep the battery between 20% and 80% charge — and not run it all day over the power. That seems to help.
338 charge cycles is not much at all! 83% is good, too. I'll bet you have several years left, given limited use (cycles) and how well it's done!