well I need 19 inches....

I tested although I am tired after a week of vjb, and I am 5 foot 10, and I need 19 inches according to this, but I think I either tested wrong(was using the side of my house, so my runningvert wasnt great.... My standing vert was the same as my running vert.... also i can already grab a 9 foot 5 inch rim, so I must have not jumped correctly when testing....