That is correct.
While that may be what is intended, I disagree with the STP rep's answer. I ordered the XL because I'm 5'5", 150lb, wear a 34-36 D/DD bra, and a 10-12 top (which is M in some brands, L in others...) and it was very large. I would say the XL is a 14-16. I ordered the L and it was still just a bit too large (in shoulders and body length) but close to a 10-12. I think I would need a P/L or maybe a M, neither of which are in stock.