I am not quite sure if that is what he is asking. If it is, then Grenville is correct.
If I am reading it correctly, it sounds like you added another provider who would need to be licensed. If that is the case, then you would have to pay for another license, but you wouldn't get another registration number. There is only ONE registration number per practice and is even associated with only one exact spelling of your practice.
When you go to the Practic/Licensing Info, it will show that you are registered and that there are x number of users licensed to use the product. Licensed users are mid-levels and physicians.
So, you could have an office with 100 users, three of which were physicians, and you would have one registration number, three licenses and as many Amazing Charts clients installs on as many computers as you wish.
If you paid for another provider license and they sent you another registration number, then I think you would have to contact AC to straighten that out.
Given I only have one provider (myself), I am not aware exactly of the process.