A license for a PiXYZ product is a “node-locked” license, meaning it is bound to a specific computer (each computer has a unique Computer ID). You cannot use the same license on multiple computers, at the same time (please see Product Terms & Conditions.).
Although, if you already installed a purchased license on one computer, you can release this license (or uninstall it) to install it on a different computer. Be careful, this action of releasing is available only once per purchased license (once a year).