In our next release we EXPECT to support
AUTOMATIC RENUMBERING of duplicate BookIDs.
Be sure you have ALL discs for both systems. The legal issues Napster et al went through are coming to Karaoke, and venues who hire "illegal KJs" are legally liable.
In time, Hosts who keep their libraries legal, will keep their venues, and pick up those venues that "illegal competors" loose as the owners search for someone who has a legal show.
Since you are an MTU customer, I expect you have purchased everything you have on your hard drive.
Oh... one thing on your question of copying songs to both machines, make sure you add the Drive/folder paths where you put the files into the Build Songs Database "Song source folders" list window. Then, the command will know to look for KMA's there.