Co-dominance and incomplete dominance are two separate deals all together, they are not the same thing. The Ball python herping world has a loose understanding of genetics, it is not 100% accurate.
Incomplete dominance is like such; Yellow + Blue = Green. When 2 alleles combine together and are represented in a mixed appearance.
Co-dominance is like; Brown + Black = brown and black striped. When 2 alleles com together and are both visible at the same time.