Do you have three sets of data in one workbook? Three separate
workbooks? We may need to get into specifics here.

To guess, given the size of the discrepencies (I was thinking in terms
of hundredths or thousandths of a unit), you may be adding too many (or
too few) numbers in some of your calculations. Are you using ranges in
your calculations? If so, are you copying them down a column or across
a row? The resulting formulae in other cells may be referring to cells
you didn't intend unless you are using absolute references.