Yeah, I just noticed that new users have both the custom, if I assign them one, and the post count titles. So, I did the check box and ran the update. This wiped out all the custom titles and just left the defaults. I just went back in and add the custom titles to everyone.
My only thoughts would be to make it possible to display just the custom title if want. It seems there is no way to turn off the display of the post based titles now.
