Frequently, a recipe you've made for 4-6 people is difficult to translate into 30 portions. All sorts of things come into the picture: how much spice (and you look at "6 tablespoons of cinnamon"and think "it's WAAAAYYY too much!") , how much salt, how much liquid, how much meat, how much onion/ginger/garlic, etc. It's tricky. If the spicing seems bland, then you need to add more, and sometimes that means more chile powder. Don't be afraid of it. Salt makes a huge amount of difference, but do it little by little. The onion/ginger/garlic ratio is often surprising - two onions for 6 people, 10 onions for 30.
However, there's a little tip I can give you: garam masala. It will resolve a whole host of problems and make the Korma taste properly Indian, without the heat.