The machine authorization limit is not seven; it is three.  You can license a plugin on as many as three different machines at the same time.  

If you want to reclaim one of your authorizations from a machine that you are no longer using, you can do that by logging into your account and going to Manage Devices. You will see a list of your activated devices, with a “Deactivate” button next to each one.  You do not need to have access to a machine in order to deactivate it.  So if your computer is stolen or crashes, you can still reclaim its licenses on the Manage Devices page.

Sometimes customers confuse the deletion limit with machine authorization limit, but they are separate.

The deletion limit is a way to prevent abuse, but we do understand that it can be an inconvenience, so we're pretty flexible. If you find that you're getting low on deletions, just contact support and explaing as to why you need to reset your count.