I find its easiest to buy the little individual size baggies that you pop in the microwave and then to calculate the points using the nutritional info. I've always done it popped, but since the individual bags are portion controlled I don't really need to worry about portioning it out.
100 calorie bags are great for this reason. I love kettle korn too, the light 100 cal kettle korn is pretty good, not as strong flavoring but the sweet is there. i always counted it after-popping
The nutrition info should give you an amount of servings. So it should matter if it s popped or not. If there are 4 servings and you eat a half a bag, you ate two.
Now if it doesn't have amount of servings, you are pretty much in trouble on that one!