I would guess it has to do with the testing methods the company used for determining the calories in the prouct. There are different ways, and the testing methods have degrees of error. In this case, there is about a 5% difference in cooked vs. un-cooked, I would guess this falls in the acceptable range for calories in the product.
Personally, when I am counting calories, I add a +/- 10% to the end of the day total, just to account for errors in my own counting ability. Monster is right though, you should not be concerned with the 16 calorie difference