VO2 Max calcualtions and oddity.

I'm in fairly good cardio shape for my age, certainly better than my wife based on how we do when cycling together. However, she gets an excellent under her VO2 max rating while I only get a good. I always thought that was a little odd.

Yesterday I went for my first run in years (she doesn't ever run) and it raised my VO2 max from 41 to 42. When I went into the user settings I noticed it has my VO2 max at 42 but my cycling VO2 max at 100. Pretty sure I never set the cycling VO2 max myself so it must have calculated it. That is a huge difference and makes me curious how they set the regular VO2 max when I never ran and they only had the cycling number to go on?