Mc does not update like most apps. Both versions will be installed.
Right. When you "upgrade" from MC17 to MC18, your computer will have BOTH installed (and your Pinned shortcuts will still all point to the old version). My server at home right now has MC15, 16, 17, and 18 all installed (not that I ever use the old ones, I'm just too lazy to remove them).
That sounds like it is what is happening here.
Either that, or maybe you think the MJR actually does the installation? The MJR is only for registering a copy of MC that is already installed and working. To install it, you have to run the installer.
Also, don't worry about the restores. The JRiver folks can reset the count for you if you ever run out. That's in there to keep everyone honest, but they aren't "sticklers" about it.