I think some of the common names can be confusing.
Callico seems to describe pure varius better than piebald does. At least when you think of piebald as pattern interupted by white pigment, like the ball pythons.
It makes it a bit more complicated with ater, because they come in many different colors. It seems like every mountain range has a slightly different look to them. Common names that include locality are a lot more helpful.