When cooking with curry powder you really should add the curry powder during the cooking process.
The reason you want to add the curry powder to the food while cooking is so that the curry powder can get cooked in with the food.
That way the dish with curry powder will turn out much better and have a better flavor to it.
If you add the curry powder after cooking then the food would not be as good and it would give the food a raw spice taste to it which is unpleasant.
Always add the curry powder to the food while you're cooking the food so that it gets mixed in and cooked in with the food and you get the best dish of food out of it.