Is Hanky Panky truly one size fits all?

I actually like to measure mine up when I buy them to find the ones that are cut the smallest...... otherwise I find that they can be a tad big on me from time to time. I'm like a size 2 in designer stuff, 0 in non-designer. These are stretchy but I think they may get uncomfortable for someone larger than like an 8/10. The non-low rise ones seem to be larger but I still don't know that anyone larger than a 10 would be comfortable in them though I don't know for sure.
 
I'm a 4/6 and if I was any bigger, I don't think I'd be comfortable in the low-rise. I have a few regular rise ones and they'd definitely be fine on someone who wears a medium or a large.