If Im not mistaken the pastel butter kingpin is only 3 morphs (pastel, butter, pinstripe).
If it was 4 it would be a more white because it would be a pastel, butter, pin, and lesser).
It should be 4... a Kingpin is a Lesser-Pinstripe. So it's Lesser-Pinstripe-Butter-Pastel. And I think it already is pretty white ... Three would be just Pastel Kingpin, wouldn't it?
0.1 High Contrast - 1.0 Spider - 0.1 Cinnamon Pastel - 0.1 Lesser Platinum - 1.2 British Short Hair Cats