If you look at the sun parameters in the animation motion lab, you'll see independent timelines for color, sun disk color and intensity. How do I set the sun disk color? The only evident control works the same, both in the Sky&fog and in the Skylab: it changes only the sunlight color, but the only timeline that changes is sundisk not color. In the motion lab there are other undocumented timelines, like sun rotation and shear.

Disc color is just the sun's color. Just that color swatch. there are some major discrepancies between what things are called in the sky lab/sky & fog palette,And what the AML and books says they are. Especially the sky stuff.