How Many Men At Arms should I get?

[Anderas]

I go up one step if there are too many potions and Mercenaries on the table.
I do not go up two steps, because somewhere those extras shall have their value as well.

Ok, if the heroes would come with 16 hirelings, maybe i would step up more than just one color. But that seems quite unrealistic to me: I've seen them coming with four or five hirelings maximum. It's the gold that restricts the number of mercenaries.