DJ, No, you have the numbers in the wrong order. The chart shows a range from +27.6 to -16.7F, which is a difference of 44.3 degrees. In Celsius, the difference is 24.6C (-2.4 to -27) which is 44.28 degrees F difference, basically the same calculation.

1C = 1.8F for purposes of figuring the difference between two temps.
Example:
50 - 40F = 10F difference;
10 - 4.4C = 5.6C difference;
5.6 x 1.8 = 10.08.