Hello,
Not very sure on what you're trying to do. Please elaborate more so we can give a better answer.

Thank you.
Basj,
Stardock Community Assistant.

To answer you, I will need to know which Fences 5 package you purchased, did you purchased directly from Stardock or via Steam? If directly via Stardock, did you purchased the 1 year Subscription or the Permanent license model?

Thank you,

Basj,
Stardock Community Assistant

If you purchased permanent license key, you should be able to activate on one system. To get more you will need to click on "Multi-Device Option" refer screenshot below.

Thank you,

Basj,
Stardock Community Assistant

If you just wish to have another "one" than just purchase it normally without pressing the multi-device Option.

Thank you,

Basj,
Stardock Community Assistant

Not sure if there is a special discount for you. What you can do is raise support ticket using the link below, use the "Ask a Question" option. Include all information details. Remember to record down the ticket number for future reference if needed. Do not raise multiple ticket, that will make your ticket back to the end of the line. Send once and wait. Ticket will be answer by the order they send in.

https://stardock.atlassian.net/servicedesk/customer/portal/4/group/13

Thanks
Basj,
Stardock Community Assistant