When I first started playing, I was only allowed to ask for Pokemon up to #151 in a pokedoll trade. Somewhere along the line (I'd guess at Collector Level 15, but I'm not sure because I wasn't watching for it), this limit was increased to "up to #386". I just now reached Collector Level 20, which has apparently lowered that limit to "up to #251".
I'm guessing that's not how it's supposed to work. Which one's right? Should I have been at a 251 limit the whole time, or should I be up at 386? Or maybe still down at 151? I'm confused.