Calculating miles between two points using Vincenty formula

Question

I have the following MySQL function:

DELIMITER $$
DROP FUNCTION IF EXISTS `fn_vincenty_distance`$$
CREATE FUNCTION `fn_vincenty_distance` (
        lat1 FLOAT, lon1 FLOAT,
        lat2 FLOAT, lon2 FLOAT
     ) RETURNS FLOAT
    NO SQL
    DETERMINISTIC
    COMMENT 'Returns the distance in degrees on the
             Earth between two known points
             of latitude and longitude
             using the Vincenty formula
             from http://en.wikipedia.org/wiki/Great-circle_distance'
BEGIN
    RETURN  DEGREES(
    ATAN2(
      SQRT(
        POW(COS(RADIANS(lat2))*SIN(RADIANS(lon2-lon1)),2) +
        POW(COS(RADIANS(lat1))*SIN(RADIANS(lat2)) -
             (SIN(RADIANS(lat1))*COS(RADIANS(lat2)) *
              COS(RADIANS(lon2-lon1))) ,2)),
      SIN(RADIANS(lat1))*SIN(RADIANS(lat2)) +
      COS(RADIANS(lat1))*COS(RADIANS(lat2))*COS(RADIANS(lon2-lon1))));
END$$
DELIMITER ;

I cannot reproduce some of the airport distances in miles. I'm using 69.2 miles as the distance between each degree of latitude at the equator:

Case 1

SFO-DFW

fn_vincenty_distance(37.6188056, -122.3754167, 32.896800990, -97.038002010)*69.2

Returns 1463.70 which is close to 1464.373 from https://www.airmilescalculator.com/distance/sfo-to-dfw/

Case 2

MIA-ORD

fn_vincenty_distance(25.7953611, -80.2901158, 41.9745219, -87.9065972)*69.2

Returns 1200.77 which is not close to 1197.062 from https://www.airmilescalculator.com/distance/mia-to-ord/

Question

How can I get the same answer being produced from airmilescalculator.com?

This is to match the calculation by airlines, for example from AA.com: