Carvin Guitars and Pickups

Does anyone know why Carvin only offers "Carvin" pickups in their custom shop guitars? It seems odd to me that you can design every inch of your guitar with Carvin, yet you are saddled with having to use the Carvin pickups. They might be fine pickups, but if I'm designing the guitar to my specifications, why can't I have Dimazrios installed? Or Fralins?

Does anyone know more about this?

I'd love to pick up a Carvin CT4 Goltop at some point, but I'd hate for the first thing I do is spend another $150 to get the pickups I want installed afterwards...