The cost associated with such parts depends on the set up. For instance, the guy I go to has a large oven. If I were to bring the parts you have over there, he would ask me if I had anything else to fill the oven, or the time may be a bit longer as he would wait until he gets enough parts to fill the oven. He shoots black and greys everyday, so that would not be a problem, but I had my motorcycle frame powdered a specialty color, and that was more due to nothing else being coated at the same time that color. I hope my explaination makes a bit of sense. In addition, the labor of masking off certain sides of the part will make a difference in cost as the labor involved is a little more. Take for instance a 10 spoke camaro wheel. It is less labor to shoot it all one color, as opposed to covering the spokes and having the outer rim one color and the spokes stock color.