I was looking for a script that did a calculation on numbers in my doc (in this case, subtracting 1 from a bunch of numbers in various formats - x, y, z or x ^t y ^t z ^t i.e. in a table) & I just found this fab script & I wish I had found that ages ago - is going to save me an immense amount of time!! It may be able to help you.
http://indesignsecrets.com/free-script-to-change-all-numbers-in-a-document-using-math.php