Licensing

A number of users listed in the client per seat tab in NT server 4.0 license manager were revoked as a user as they had left the company. This was carried out on the BDC, however the users have reappeared in the client per seat list in license manager. Can you tell me why the users have reappeared, and how do I permanently delete them? I was wondering whether I should have deleted the users and not revoked them, does this make a difference?