Does table of contents (even if it's the overlay type) increase project size?

I made all of my projects 800x600 to fit an unfortunately rigid LMS, and I noticed that for the few that I added a overlay TOC to, they come out slightly bigger (I can tell because the 800x600 box that the LMS opens the trainings in has scroll bars only on those).

Has anyone else experienced this? I'd really like them to open in exactly 800x600, if possible.

Thanks!