I think it would be helpful to ask the seller/ breeder what the parental genotype was. In Stefan Broghammers account ( author of Python Regius) he discusses this. He says in part, “It has been realized that mating two low white pied specimens will only produce low white pied young. However, it’s not the same for heterozygous specimens. If you pair a low white piebald specimen with a non pied there is is a chance that the white content is not exclusively determined by the pied parent but also by the non pied parent , meaning the hetero specimen exerts an influence on the phenotype of the offspring as well. He goes on to say that this scenario exists in the Calico for example, where the appearance of the offspring is not determined by the dominant Calico but rather by to what extent the respective mating partners genes respond to the mutation. This could also be the case in piebalds. Important to look at parentage when possible.