I have found that size charts routinely do not mean what they say.
Many times, the waist measurement for the size I wear is 1-2 inches smaller than my waist. But the things fit me. If I got a bigger size, they would be too big.
I don't like ordering from STP. The orders take a long time to get here. I have returned stuff, no issue, but sometimes it's taken so long for stuff to arrive, I almost have forgotten that I placed an order. Plus, they have that religious stuff on their site. I try to ignore it, but really. What would people think if I put Judaism symbols on a web site? I am sure I would hear about it.