The Power Ratings are based on "Strength-of-Schedule", "Offense Rank", "Defense Rank", and "Total Power".
The first number listed on the left side is the final ranking when all of the above are factored together.
Take a look at the full list at the address provided below.
Also, just eliminate any out-of-state teams that have a "-??" by their name -- these were needed to get a true "strength" measured since most of these teams played around 3-4 matches in tournament settings.
So, A.C. Flora would actually be #20 instead of Pope John Paul of Canada.
Massey Ratings for S.C. High School Boys Soccer