How to reliably determine total pages

Hello all,

I'm working on a program that generates a report which includes a "Page X
of Y" description in the corner. I'm struggling trying to get the total
number of pages to reliably be calculated. I'll try to explain how it
works now. The program does the "two-loop" approach where it reads through
all the items it will eventually print to try to calculate a total number
of items. I believe this part of it to be working correctly (but I could
be wrong).

At the end of this first loop it attempts to calculate the total number of
pages. I'll preface this by saying that this report basically has what
I'll call a "header" page and a "continuation" page. The "header" page
prints mostly heading information and one or two detail items. Then the
"continuation" page just prints detail items. Here's how the calculation
currently works:

if total number of lines > max allowable lines on "header" page
then total lines = total lines - (total lines - max allowable on "header")
- 1
total pages work field = (total lines/max allowable lines on continuation
page)
if the decimal portion of the total pages work field > 0
total pages = whole portion of the total pages work field + 2
else
total pages = total pages work field + 1
endif
endif

This works sometimes, and sometimes it doesn't. It doesn't appear to be
as simple as just dividing the total number of lines by the maximum per
page, because we have two different maximums (because of the whole "header"
and "continuation" thing).

Hopefully this isn't COMPLETELY confusing. Anyone out there know of a
really reliable formula for computing this when two different max lines
amounts are involved? As always any help is appreciated. Thanks!

Bill