17th ed of Chicago Manual of Style Notes and Bibliography ibid vs. shortened citations

In the 17th ed of Chicago Manual of Style Notes and Bibliography ibid is abandoned in favor of shortened citations. I’ve been experimenting with the Chicago 16th Footnote Style and as far as I understand, the Footnote Templates’ short form setting for including title to disambiguate citations only work at one level. Example on what I get:

1 Glover M. Allen, Bats: Biology, Behavior, and Folklore (Mineola, N.Y.: Dover Publications, 2004).

2 Glover M. Allen, Bat Behaviour (Mineola, N.Y.: Dover Publications, 2006).

3 Allen, Bats, 34.

4 Allen, Bats, 54.

5 Allen, Bat Behaviour, 123.

6 Allen, Bat Behaviour, 34.

If I’ve understood the 17th ed correctly, footnote 4 and 6 above should have been:

4 Allen, 54.

6 Allen, 34.

Grateful for any confirmation or other feedback on this.

If that is the case, how would the reader be sure of which of the two sources those page number is from?  It would seem they then have to find the exact “match” which would be cumbersome?  

added in edit, Oh – i guess because it is the one right above it “ibid” but if there were only one book by this author about bats.  but I let the publishing house deal with these issues.  I think more information is better, but I don’t work in a field that commonly uses footnotes.