Here's another recruiting service's rankings:
http://rankings.asgrbasketball.com/...leases-top-75-recruiting-class-rankings-2017/
Honestly, every service goes about things differently. Some use quantity over quality, so a two-player class wouldn't be ranked as high. Some use an average rating of the individual players, so that is all about quality and not numbers. Some even count transfers.
Regardless, the rankings are just subjective. It's all about how the players from different classes mesh and complete a team's roster. I have no doubt that Chasity and Rellah have skills that will allow them to compete for minutes/starting spots and contribute as freshmen.