It varies based on skill, IMO. For whatever reason, some skills are more commonly programmed with significant room for improvement than others. In my (subjective) experience, LP, PER, and STA are most likely to be high-high. ATH is most likely to be low-high. The others are somewhere in the middle. And it does vary somewhat by position (for instance, I see more PF and C with high-high REB than SF's with high-high REB), but probably no more than the distribution of high vs avg or low potential. It also varies by how high they already are. Obviously, nobody over 73 is going to be high-high.