Hoster 3.108 is now released.
Go and get it now if you have upgraded to 3.0. If not, buy the upgrade.
UNCLE! 
We are finding several ways to retain the BookID structure we now have.
Your song books are safe. Your backed up discs are save. BTW: Even if we did renumber the BookID, it STILL would refer to a DiscID and Brand.
Fear of the unknown has run rampant here. There are so many incorrect assumptions, as well as your request for not changing, that I can't take the time to ansewr.
I am closing this thread.