Somehow installed 360 on new PC without deregistering old one

A couple of months back I got a new laptop. Since 360 was already installed on the maximum 3 computers, i uninstalled it from my old laptop, did the norton support thing to deregister my old laptop from the subscription in place of my new one, and installed it on my new laptop. That worked fine. However, earlier today I did the same for my brother's new laptop, but forgot about the norton support part.  It somehow worked, though theoretically it would mean I've registered 360 on 4 computers. I realised a moment ago and checked my norton account and it says I've got 2 installs remaining from my maximum of 3, despite the fact I've unintentionally already gone past the maximum number of installs.

 

Whats going on, and what can I do to sort it?

A couple of months back I got a new laptop. Since 360 was already installed on the maximum 3 computers, i uninstalled it from my old laptop, did the norton support thing to deregister my old laptop from the subscription in place of my new one, and installed it on my new laptop. That worked fine. However, earlier today I did the same for my brother's new laptop, but forgot about the norton support part.  It somehow worked, though theoretically it would mean I've registered 360 on 4 computers. I realised a moment ago and checked my norton account and it says I've got 2 installs remaining from my maximum of 3, despite the fact I've unintentionally already gone past the maximum number of installs.

 

Whats going on, and what can I do to sort it?