I see what you mean now - a 10th grader can not play down because he said he will PG after his senior year - PG means that you completed all 4 years of high school and will be PG ing ( post grad) at a prep school - when you are in your prep year the team plays a college schedule never against high schools - maybe what is happening is parents might leave a child back when they make a transition into a private or prep school in 9th or 10th grade having the student repeat the grade Vand then the player will play down which is an advantage to the team for sure but it's not a PG player - he can then PG somewhere too and get another year of growth in the sport-