I have a 700 ST with 1000 miles on it. I get about 21-22 miles throttle only when traveling on a flat surface, no headwind or tailwind, and speed not greater then 20 miles per hour. The faster speeds really eats up the battery. I also readjusted my percentage voltage readings so they are more accurate.
Cool test. As someone else mentioned, it is best to use voltage for more accurate readings. Mine can go up to 54.4V full charge and I have approximated I can go down to ~42V before it turns off. I modified the settings for voltage according to Ride1Ups youtube video for the display. Be aware of voltage sag as well, the quirk of e-bikes where the display will not show the actual battery left and you must stop using the bike for a few minutes to get the right amount again.