Thats because Pantone usues their own master colors to create the books on paper and us mere mortals do not have access to them. You'll notice for instance that Pantone only uses their 800 series of colors in the expanded 800 series offering. Take 186 red; the Pantone formula has three ingredients (warm red, rubine, and black) while the Rutland formula has four (flo red, scarlet, red, and white) with no black. The overwhelming largest component is the flo red, which Pantone doesn't really even have (closest is 805) Now CCI claims to have matched the Pantone colors as PC ingredients for their DC formulas. I have not tried their system out due to lack of need to do so but if they have well that was smart.