I have a double-monitor hooked to a main PC for gaming, and next to my desk is a mini-ITX PC hooked to a monitor for server and miscellaneous activities. Is it possible to run DisplayFusion Pro Standard/Personal/Steam-key when both PC are active at the same time, or is it strictly one license per one active device?

P.S. If I purchase a Steam key license and lost access to my Steam account (like if it gets deleted), is it still possible to recover the DisplayFusion Pro license? (e.g., through an email receipt as proof of purchase)