A SuperLab license is perpetual (no renewal every X months). All 4.x upgrades are free. You only pay if you want to upgrade to the next major version. I’ll double-check on the network installation issue and post a follow up.
SuperLab can definitely be used in a network. If you’re already running the Sassafras KeyServer software, we can get you a license file to install on the server that will allow you to run SuperLab on any client machines on the network as needed only limited by the number of SuperLab licenses purchased.
Otherwise, you’ll receive a license number, and you can activate and deactivate machines over the internet as needed. One license is tied to a given machine until you decide to manually return it to the server. This does mean that you can move licenses between machines, but it’s not automatic–it requires a small amount of intervention.