Universal has never filed a permit for an “A” or “B” location in a soundstage that holds a single house. Historically, if a soundstage holds a single house, then the permit is strictly for the soundstage.
A big reason for that is because the existence of a “B” implies the existence of an “A.” As such, every entity that looks at and uses these permits (inspectors, contractors, county officials, Universal employees, etc.) - if they see “24B” will automatically assume “24A” exists as well. An administrative error that just happens to say “24B” when a “24A” is not planned is going to cause a lot of confusion. Universal would have likely addressed that before submitting for the permits at all (at least, they should have—but they’re remarkably amateurish sometimes).