Reply To: . Pages, Point pages, Sub Pages – help needed

There's no way to do this with the automatic page numbering built into InDesign, but there is a way to at least reduce the pain.

1. At the page immediately after the one where you're going to insert the “point pages” use the Section and Numbering options to create a new section. Turn off automatic numbering and type in the current page number as a value for the starting page.
2. Insert your new pages, but override the automatic page number on each new page and replace the automatic value with the explicit “point page” number (7000.1, 700.2, etc.)

Unless you have dozens of these per issue, it shouldn't become too unwieldy. I assume that the client “resets” the book every so often, so you get a fresh document every so often without (or fully incorporating) the inserted matter that lets you begin the cycle again.