Krzy sends:

I looked at Johnny Durand's flight (and Dustin's) from Quest Air on April 24,
2007. It was 456.2 kilometers or 283.5 miles. Both WGS-84 ellipsoid.

Therefore Krzy has set a new eastern US record (as I wrote earlier).

Just why XContest recorded the flight at 455.66 km is not known to us. Perhaps
they use the FAI sphere.

https://fai.org/page/world-distance-calculator