Because its an average which includes people who pay $0.00 for their 4 years of medical school thanks to their willingness to serve in the military, or their extremely rich parents/uncles.
And, to account for the save cost average between the schools despite an 8K/year difference, I would assume, based off a conversation I had with a fellow applicant who was paying his way through military service, that he didnt even look at the cost of the schools when applying, whereas I am planning on taking loans out and paying them off over time, possibly with military commitment after residency, I didnt both applying to overly expensive schools...So, using his and my way of looking at the schools, I would be willing to bet that there are a greater number of people on military scholarships at CCOM than at PCOM...but thats just a guess.