exporting from quickbooks
 

I'm trying to track scan rates from my stores. I have quickbooks so I export
data of what items I've shipped to one sheet, what I've sold of those items
to another, and the third sheet contains simple division formulas to give me
scan %s. This works fine until I export new data to the first two sheets.
At this point the sheet with the formulas gives back a REF# error. I have to
retype the formulas on the third sheet every time I export new data from
quickbooks to get it to calculate. Why won't it recognize the new values on
the first two sheets?