5'8", 136lb, Under Muscle - 330cc vs. 360cc?

I always suggest that if a patient is having difficulty choosing between two sizes, to go with the larger implant.

In any event 30cc is about an ounce - not much to worry about.

30 cc is actually a very small different and most surgeons will adjust you upwards following sizing to account for placement beneath the muscle.  That being said, the size is probably very appropriate for you.

I hope that helps!