...does the document shrink on the .pdf? (I've already asked this at the Adobe Acrobat forum and they said it was the wrong place.)
I have some drawings with rulers on them in a book I'm writing, and they HAVE to come out at size. Some time ago when a booklet was printed, everything on the page was reduced. I don't know if importing to .pdf did it, or if that's something the print shop did (which is now closed, so I can't ask them).
When you print the booklet, or when someone else prints it, you have to check the Print dialog box carefully. Often times the default is to Fit the Page, and the it's not noticed. There is no reason that a PDF should be reduced in size. You can view the dimensions of the PDF by pausing over the lower left corner of the PDF. A popup will show the dimensions.
A popup will show the dimensions.
You can make that permanent.
Just change the preferences in Acrobat Pro or Adobe Reader:
Preferences / Page Display / Page Content and Information / [x] Always show document page size