OK, I just picked up the Centrotec bit assortment kit. Why does it come with two Centrotec chucks? I would think one would have been enough, in the event you wear one out it can be purchased later. So I was waondering all weekend what I am missing in my logic. Heck, I woul dhave loved to see them add somethign else to the kit that was not included. So, are there any wiser folks than me out there who have the answer I seek?