Importing .ibooks files with close names

Cannot figure this one out as I created TWO .iba files. One titled

Roofing Boston

and the other

Roofing Boston Flat

Both .iba files are almost the same except for a few slides but these files are different.

I checked to make sure the name in the title bar is correct as well as the Book Title window area. There is ONE chapter in each book and I named the correct title chapter

Also checked the inspector to make sure each one is titled correctly.

When I save to .ibooks I import one file to the .ibooks app and it opens and displays correctly. But when I import the second title I get the message that the book is ALREADY in the library. So after a few times when I got the message I replaced the file with the new title and sure enough the NEW title appears with the old title name. Very confusing as I have been using I Books for a while and I'm guessing that the title of the book is somewhere else in the file?

Any help??????