a former Rivals executive once told me that "measureables" for recruits came from whomever they could get to give them a number. Could be recruit, Mom, Dad, Sis, Bro, HS Coach, girl friend, aunt, uncle, whomever... didn't have to be validated...
You ever wondered why once kids get on your campus they are rarely as fast as they were in high school?
You ever wonder why once kids get on your campus they are frequently shorter than they were in high school?
You ever wonder why once kids get on your campus they are frequently lighter than they were in high school?
all of the above happen more often than kids matching what recruiting services have for them.
Recruiting services are in business to make money. To market to fans, then fans have to have interest in those super high school players. Embellishing measureables seems to be one way to gain fans interest. Like showing video clips of players "special plays" and not showing video clips of players "bad plays". More bad plays than good plays.