The science that Crostfree had was something that worked differently compared to the stronger Presiders.
Domain was classified as a Presider Level tech. It was a foundational science that allowed them to create changes in the fourth and succeeding dimensions. As for Crostfree, he was very knowledgeable about Domains because the foundational science that he pursued allowed him to peer into these dimensions. Both sciences were among the options that a Presider may claim upon reaching this level but these sciences. But if a newly ascended Pioneer would immediately claim this, it would probably be several hundreds of years before they could even make any sense of it!
