Its also possilbe that whatever gene responsible for the het pied marker is a totally separate gene from the piebald gene. If the marker gene is positioned near enough to the piebald gene on the chromosome, it should be linked and inherited with the pied gene, which is why it tends to show up frequently in het pied animals. Like everyone is saying, this is definetlely not cut and dry, especially since there is no sequenced genom information on ball pythons and we really have no idea what genes are actually responsible for what mutation.