But yes, in the Implementing Regulations document, they are pretty specific that supervisors must be independently-licensed:
"In interpreting this provision for internship programs, the CoA looks to determine appropriate credentialing of the supervisor on the basis of jurisdiction governing the practice or service that is being supervised, provided the credential is generic in legally qualifying the holder for the independent practice of health service psychology."
So basically, someone who requires their own supervision wouldn't be allowed to be a primary supervisor, and I believe any supervision they provide would not count toward the required 2 hours per week of supervision provided by a licensed psychologist (unless their supervisor were also in the room, perhaps). There may be some sort of technicality if the supervised provider is receiving supervision on their supervision (as confusing as that seems), but if I were a director of training, that's not the kind of situation I'd want to put myself or the program in, nor is it something I'd want to have to try to explain to APA.