Whenever you add a type parameter (Boolean = yes/no) to a family type, this parameter of every other family type will be set to true as well. I don't really understand why this works that way. I have a family with 100 family types and every time I add a parameter I have to manually set this parameter to false for all other family types.
In my opinion its best whenever you add a Boolean to a family type, to have it set to true for the current family type only.