The answer and signature look reasonable to me. It looks like they didn't specify it, and just assumed, people would know they were buying a single user license to install on computers they own; which is common. If you want to get technical about it, and their T&Cs don't say otherwise, you could probably argue your case though with CC company etc.
If you want to install on friends PCs and bypass their intentions, then you need to pretend your friends PCs are your own and follow that procedure.