Yes, I agree that wouldn't normally pose a problem -- in a real-world situation you would rarely ever want to recreate an account immediately after deleting it, although it could happen in the case of a silly accident such as deleting the wrong account.
However, when testing, something like that can be very disconcerting if you're not aware that it can happen. In other cases I was able to repeatedly create and delete using identical account details, without any lag. Which only made that particular instance more puzzling.
I wasted a lot of time trying to find a problem with code, account configuration, etc when there was no problem to be found -- at least, not one that I could do anything about.
But two days -- even one day -- seems to me to be an extraordinarily long time to be locked out from a repeat attempt.
I suppose this is a "feature" of IIS ????