In retrospect, you're right about her weight. The pictures my boa-keeping friends saw weren't great, and I'm not used to boas enough to tell; I'm generally a python person, and blood pythons look like land whales compared to Peanut Butter lolShe’s definitely hypo and I don’t see any Central American influence. Super Hypo isn’t uncommon and isn’t worth more than most hypos unless they have been proven through breeding and even then they have to be quality to be worth real money. Orange tail is a line of Hypo but without documentation can’t be claimed. Hypos are honestly a dime a dozen even though your new foster looks like a nice clean one with some decent coloration!
She honestly looks perfectly healthy and not skinny at all. Most people grossly overfeed boas. She looks like a loaf of bread/boxed off and muscle tone which is a sign of a healthy boa. I’d be surprised if she’s actually anywhere near 20 and is most likely way younger & a good size. 40 isn’t a common age for boas to get to even though they technically can. Mid 20s is a more common lifespan if the boa hasn’t been fed to death.
Also boas are generally smaller than people imagine them haha. You can get some real big ones but average is actually 6-8ft for them. And Boa constrictor imperator have been upgraded into their own species they are now just Boa imperator.
She's muscular and powerful, but she does seem stunted for a boa that's supposed to be twenty-one. My close friend had a boa named Butters who was eight feet long at only ten, but for the most part Butters is the only boa I've been close to in my life. Maybe she was just enormous?