Excel only maintains information on cells it thinks are in use. This can
include cells that contain formatting, change in row height, etc. They
don't necessarily need to contain information. If you use the vertical
scoll bar and when you get to the end of you data, it isn't on the bottom
end of the bar, the Excel is seeing a lot more of your sheet as being in use
than you would think. This can cause excel to store much more additional
information and could be the cause of your problem. To reset the usedrange,
select entire rows from below the last filled row to the bottom and do
Edit=>Delete. An easy way to do this is to go in the name bar in the upper
left of the formula bar and enter
300:65536 <cr>
Then do edit=>Delete
Do it on each page with the appropriate ranges. Then save your workbook.