Count them at design freeze. A character with four sprayed colours is four masks; if the same colour appears in two separated places, that is often two masks as well, because one opening cannot reach both without over-spraying the middle.
Pad printing is the alternative for flat, well-behaved areas — eyes, logos, simple flashes. It is cheaper per colour and prints on curved surfaces reasonably, but it struggles on deep recesses and on parts that flex. The practical mix on a small figure is moulded-in base colour, then sprayed gradients, then pad-printed detail on top.
Colour drift across a long run is the other reason to keep the count low. Each sprayed colour is a mixed batch, and each batch is a chance to land slightly off the approved chip. A six-colour figure needs six colour checks per shift; a three-colour figure needs three.
If the artwork is still moving, ask what a mask costs to re-cut. The answer tells you how much design freedom you actually have after sample approval.