The better pitchers I've measured typically have greater spin on the rise than the drop. I figured it is because it is easier to impart spin on a rise.
Got mine! It didn't register most times when I spin it at my side, but clocked almost every pitch. RevFire User Manual says "The RevFire 2 must be thrown with a full windup to register a pitch in the RevFire app." My daughter is working now to figure out how to fake out the windup :).