Whatever the serving size is on your package, the calories listed corresponds to that. If you use twice the serving size listed, double the calories (or enter two servings). If you use half the serving size, halve the calories (or enter .5 servings). If what you use is the same as the serving size, enter the calories indicated for the serving size. Don't forget to add in the nutritional info from your milk as well.
And now that you don't have to be perfect, you can be good.