Well, I hope that someone will remind me where this checkbox is now—but in case it is on an extended vacation, or gone for good—I started googling and found my own blog post from a few years ago on how to use Acrobat to split a PDF at top level bookmarks. (Yes, it's been one of those days.)
Splitting the PDF was way quicker than saving out each .fm file to a .pdf one at a time.
Currently it is not there. Thanks for sharing the blog post on splitting PDF at Bookmark level. Really informative.
Thank you for clarifying that. I was rushing to get a job out the door and I thought it was me!