How exactly does Southwest define a "trip"?
IIRC, it had something to do with the flight time from DAL-HOU, which is like :55. One trip (or :55 minutes of flying) payed $77.50. So converted to hours, one hour pays $88.
If this is correct (or something very similar), then the APC rates are completely correct. The problem with your analysis is you are comparing BLOCK hours flown to pay per trip. You are essentially including trip/duty rigs and such into hourly pay. If we took some senior legacy international pilot, or some super senior guy on reserve who bids not to fly, using your method, I am sure they would be making $400 - $500 an hour. But that is not how the system works.