Is your current license for ver. 1 or ver. 2 of Start11?
There would be an upgrade path from ver. 1 to ver. 2, but that would be for your current license,
If you need a second license, that would have to be purchased, but you could upgrade to a Multi-Device license (5 installs).
Click the small blue "Upgrade" link on the purchase page. https://www.stardock.com/products/start11/ for the Multi-Device purchase and follow the directions.