The GPS box is not used for timing the rider, only for the broadcast? I'm thinking here, if it was used for timing, mounting it further back on the bike, if passing a certain point on the track was the start marker, should make for a faster time. DH racing is a standing start formula and if the box 'crosses the line' later, it will do so at a higher speed. Thus the average speed over the distance should also be higher and thus the time shorter?