Exactly, if the wood sounded better, I imagine they would make all their guitars out of it. I doubt its a matter of cost, because if the wood costs more, sounds better, and looks more beutiful, they can charge more for the guitar, and that makes sense from a business perspective. So, thats what they do. They have limited stock on special woods, and therefore provide an additional option at a higher cost, for the same components and manufacturing technique, Capitalism at its best.
Does that make any sense?