Once again, with KP, im pretty certain it goes back to your application+nomination status. I know if you are struggling in a certain area, USMMA will sponsor certain applicants to do a prep year. I'm sure coaches recommend prep school to certain recruits, but I don't know if they actually can get them sponsored slots just for being an athlete. AF, Navy and Army can grant athletic appointments to their prep schools (ie. USAFAPS, USMAPS and NAPS) since they are D-1 and have slots specifically for athletes.