Not really sure about that. If you only add sauce and cheese and put the pizza in the oven you will get less gralats. If you add 3 toppings you will get 6-17 gralats which is for every topping. I get the closest ingredients. So I only use sauce, cheese and the toppings sauce and cheese. You get the same gralats as the others.
I'm not sure if this is a bug or something but if a pizza is in a oven you can put another one in and it will disappear from your peal and you will still get gralats. It doesn't work with the normal speedy pizzas. From my experience it works at the 12.5k floor and the one below that