I am 5'7 and about 160 (this fluctuates 5lbs either way), and Jerry's XL is also *way* too short on me, and I am even what I would consider "short" waisted. FWIW I fall at the upper end of the Large measurements currently, and I wear a large in most brands now (and occasionally a medium).
I agree that if you can try on both that would be best - girth for most dresses (and leotards/dancewear) is really more important than the rest, as all of these garments are constructed with a fair amount of negative ease (meaning they are meant to stretch, often by quite a lot).