There are a number of recent factors causing higher boarding numbers. First SWA is now placing people on the same confirmation as a Alister in order and doing the same with companions. Other considerations include the number of passengers connecting with your flight, they may have checked in earlier since the could checkin at T-24 of their first flight. I've had numbers that high at t-24 but even as A-List O have noticed ,my boarding position is higher than it used to be,.