MACON — It was described as a cross between the BCS and NCAA college basketball, and it’s coming to high school sports in Georgia. It’s the new power ratings system, which will determine which teams advance to the separate public and private Class A state playoffs, and how they are seeded. Monday at the Macon Marriott City Center, the Georgia High School Association Executive Committee put in place much of the structure for the upcoming 2012-2013 and 2013-2014 school years, including how to manage the switch from five to seven state champions.