If you have two Separate Licenses, you have the same rights as 2-License; you just bought them Separately. They would need to be Synced, and either way allows you both to be working in the same file at the same time or not, as long as you also set up the Sharing. If you have one computer, you would have One QB license, but have two different data files. There is no limit on data files; this is like Word Letters. So, Multi-user means "access shared files at the same time" and it requires # of Licenses for the # of expected concurrent users. 2-Licenses = the right to install it on two computers, even if you never intend for Multi-user sharing to be part of your own system process.