We're trying to create a document template that changes its bottom margin
depending on the total number of pages.  A one-page document should have a
1-inch bottom margin; two or more pages should have a two-inch margin.

The solution we found was to insert a formula in the footer of page 1:
{IF{NUMPAGES}>1"       "}{IF{NUMPAGES}=1""}

That space in the first formula is a one-inch tall white image.  So when a
document exceeds one page, Word essentially inserts our little white space,
inelegantly increasing the bottom margin to 2 inches.  The second formula was
added so that if you type a two-page document, then delete a page's worth of
text, the footer will revert back to containing no 1-inch "blank" graphic.  
In theory.

This works wonderfully in Word v.X (OSX).  Unfortunately, in Word 2003
(Windows), the formula only seems to kick in when you force Word to count the
number of pages.  Printing or opening print preview does the trick.  This
situation gets even stickier in the complex case of typing for two pages,
then deleting text and hoping it will go back to the one-inch margins.

Question 1: How do I get Word 2003 to constantly check on the number of
pages so that my users don't have to click "print preview" in order for the
formula to kick in?

Question 2: Is there a way I can improve my formula so that the solution is
a bit more functional?  (Something about the way we've written it doesn't
settle well with me.)

Question 3: Is there a better approach that will work cross-platform that
I'm somehow missing?

Thank you!