Add Standard Index....then it automatically saves each section??

I have a manual created with 12 different sections including the front and back. We market the same machine as 4 different brands. With the difference being only 2 decal placement pgs in 1 section, I just create 1 book that includes the 2 decal placement pgs for each brand so I only have 1 book file and 1 of each section file to maintain.

We print from PDF.
To create a print PDF for Brand A, with all the section files open, I temporaily delete out the 2 pages for each of brands B,C,D (without saving back to disk). Update the index and create a pdf.

The problem I'm running into with frame 8 is when I temporarily delete those pages without saving and then go to add standard index, for some reason it automatically saves back to disk each section at that point in time, thus losing the decal placements for brands B,C,D I deleted.

I never had this problem with frame 7.2.
I'm thinking there must be a setting somewhere to keep it from doing this.
Does anyone have any ideas?

Thanks!