Length of time deleted users stay in the DB

I screwed something up in my site and i have to add users to new sites a weird way. And i always forget i have to add them the weird way.

If i dont add them the weird way way it wont work and i have to delete the username/email they want. and add them again.
After i delete the username and try to add it again right away Wordpress always tells me this username is already taken but will be deleted in a couple days.

how do i allow usernames to used right away even if they have just been deleted?