Why Catamarans Are Cheaper Than Monohulls!

CatamaranFreedom.com/Prices The data I have compiled on my website shows that a catamaran necessarily isn't pricier than a monohull(a.ka. regular sailboat), in both examples we can see that catamarans are both cheaper and more expensive than monohulls in their respective category. So what is it that makes the difference?