I'm in the same boat.
Actually, when upgrading the user to the premium usergroup in 3.8.6, it worked instantly. Using the same upgrade script (even with define('DISABLE_HOOKS', true)

I have to run the Update User Titles script.
I've considered tearing out the code used for updating users and running it for just a single instance, but that sounds like trouble (at least with me doing it).
I'm not sure what changed from vb3.8 to vb4.1.1, but then again, I've been saying that all month.