Hoster upgrade to 4.0

[stublack]

Question 1:
If I have two computers with the same registration code.
Do I need to pay for upgrades for both laptops?

If yes, will these two laptops then have the same 4.0 registration code?

Question 2:
If I have a computer that has no back up computer - in other words the only laptop with that registration code. If I make an upgrade can I then add a free backup copy with the same registration code to another brand new laptop that has never had hoster loaded on it?