"He who marches out of step hears another drum." ~ Ken Kesey
Heres my reason the formulators are adding white. If they do not the wet color is completely transparent and will appear significantly darker in hue than a printed and cured swatch. In other words it's faster to arrive at an approved color. They aren't used to matching these inks and this is a bit of a bandaid. They do not realize that white can cause the inks to gum up and dry quicker.