Their licensing is weird... one machine for Synthesizer-V, but up to three machines for the voicebanks.
You can activate and deactivate a license so you can move Synth-V to a different machine. I've never tried it, nor have I tried running it on multiple machines with a single license.
For me, it's inconvenient to keep activating and de-activating, and I ended up buying a second license of Synth-V for my laptop, but only one license for each voice I have. That has seemed to present its own set of problems for updating versions, but at least it always works for me on both my laptop and my desktop, whenever I need it.