I have tested it on multi-site and it works just fine. However, the tricky thing, in some installs, is to make sure the users have the right role assigned for the correct site to make sure they are treated as wholesale customers. One person had some issues with users that had roles on several sites, and it was a bit tricky to get that resolved, but it was just making sure the person had the right role and capability, and nothing to do with any code in my plugin.
I’m fairly easy going with my refund policy, so you are welcome to purchase and give it a try. If it’s not going to work for you, and not something I can quickly fix for you, I will refund your full purchase price and simply revoke the license.