InfoPath Dev

I imported an Excel workbook into an Infopath form. It was a simple spreadsheet with 3 columns.  Price Tax Cost

The Cost colum had a forumula  =SUM(A2,B2).  I verified that it worked before the import. When I did the import the structure was there in the Infopath form, but when I ran the form the addition didn't happen. Can Infopath do that? Meaning...add values of textboxes, and or import excel formulas?

Okay...I figured out how to sum two fields in a repeating table  Set the formula of my "Cost" field to     sum(field1) + field2 

Fine... I was hoping to just have the import do all that. So as to prevent manualy having to "re-program" a form with all the formulas from the imported spreadsheet. Any thoughts or suggestions? Has anyone done that?