making a single page PDF to a multiple page pdf with exactly the same page

That's the quickest and easiest way to do this. Even if you need a large number of pages (e.g. 500), this process is much faster than creating a script (and I know how to whip up scripts in my sleep 🙂 ). The key to doing this fast is to use keyboard shortcuts: Ctrl-A will select all pages, Ctrl-C will copy then and Ctrl-V will paste them - on a Mac, it would be Cmd-A, Cmd-C and Cmd-V. So you can just repeat the sequence Ctrl-A Ctrl-C Ctrl-V a few times and end up with about the number of pages you need. You can either stop just before you hit e.g. 84 (which would be at 64 pages) and add the remaining 20 pages with a manual selection and then copy and paste, or you overshoot (to 128 pages) and remove the additional pages by selecting them and hitting the delete key.