All templates I have seen require some editing. I don't know what others do, but I will try to spend time to understand how the presentation works. For example, if I want a "30-page" book, I try to see how this can be done and still maintain the integrity of the original work. I did this last year for a couple of the book templates. (Note: always work on a copy of the template when trying to "doctor" it up.)
Rather than making two versions with different endings, I've tried this and it seems to work (comments and suggestions welcomed!): I created two slide styles (1) 4 Second Fade to Black, and (2) 12 Second Fade to Credits. Now, adjust the music timing to fit, replace the image as needed and the final comment. I've attached the styles I created, if you're interested.
4 Second Fade to Black.ptestyle
12 Second Fade with Credits.ptestyle
Finally, a big thank you to Barry Beckham for the teaching videos!
John