Why's that? Duracoat sells camo kits meant to be applied on top of each other.
You're right, they do. But I'm personally not a fan of multiple layers of paint that is difficult to remove. I guess, if you have your paint scheme figured out and have practiced it a handful of times and know that's the one you are going to go with that required multiple colors; then yeah, I would go with the duracoat.