Formula not calculating in excel layout
I've created an Excel layout with two columns. In the thrid screen I've put one simple excel formula (column C= column A- Column B). However when I execute the layout the formula doesn't work it seems. I've 100 in column A and 85 in column B. That means I should have 15 in column C. However I see 0 there. The same applied to other rows as well.
Please advise what is that which I'm doing wrong? Is there something specific to setting up excel formulas in BPS excel layouts?