(* 4.0 (atan 0.1)) = 22.842 degree
(* 4.0 (atan 4.0)) = 303.855 degree
I'd rather use (42 . 0.098491403) - (* 4.0 (atan 0.098491403)) = 22.5 degree
And it's complement (42 . 10.15317039) - (* 4.0 (atan 10.15317039)) = 337.5 degree
But my final guess is that 0.1 and 4.0 are Ron's lucky numbers...