Printing spreadsheet print area to 1 page fails to shrink image en

Print scaling fails to shrink image enough to print on one page (even though
Print Preview shows the data fitting in one quarter of a page). If I try to
scale the data down to 85% manually, all the data fits on 1 page, but if I
use the "1 page" options for width and height, the image runs off the bottom
of the page. My selected print area is 13 columns wide and 50 rows high. I am
printing it in landscape mode.
Why doesn't the Print Preview fill the same percentage of the page as the
actual hard copy does?