I know we can use the field to not show duplication, but it is not working? Why? because it is looking only at the title. There are so many Authors that use the same Title, Hell a few even use the same title in different series they write. Can you add a check that will look first at the Title, then the Author, then Series if all the condition is met then and only then do you have a duplication, other wise you have different books and should not be asked. Movies are the same, but a different year when producted.
Audiobook books could have several the same year. But by different authors and different genre.