I've got exactly the same reply from Ben too. Since I don't have laptop, by installing Spark on my desktop machine, my SparkLE is not that mobile anymore. I've asked if I could install my Spark program at my work machine too (my second desktop, it's just I'm keeping it at my office since I use it as my work machine).
Ben told me, there should be no problems using same authorisation code od both of my machines.
Cheers!