Some thoughts:

(1) Have you set a minimum font size here that might be larger than the specified size:

Firefox > Preferences > Content > Fonts & Colors : "Advanced" button

(2) There might be a problem with a stuck file in the cache. Could you try a "Shift-reload" to bypass the cache and see whether that makes any difference?

(MAC) command + shift + r
(WIN) ctrl + shift + r

(3) Could you have scaling set to greater than 100% under:

File > Page Setup

(In case you do not use shrink-to-fit in the print dialog)

(4) Do you have any add-ons that might affect printing?

Thanks for the quick response.

1 - No minimum font size set

2 - I tried bypassing cache, no difference

3 - Scaling set to 100%

4 - None of the add-ons should affect printing

All the headers and footers are set to -blank. I reset some of the print.print modified preferences but that didn't make a difference either.

I finally reset the browser to default settings which added back the title, url, page number, date/time in the header/footer. Printing like that still rolls to a second page but much less data is wrapping ???

When you set the header/footer to -blank does it artificially add to the top bottom margin?

I don't think the margins change based on the header and footer; I think the default margins are extracted from your printer driver somehow. I'm not sure how you can adjust those (on Mac OSX) without creating a custom paper size (as described in this article: http://www.mintprintables.com/print-t.../adjust-margins-osx/).