Swing iwatch app

Anybody using the Swing iwatch app? I’ve using the free version on a few practice sessions. Curious how accurate it is since it states I only hit 14% backhands and my fastest racket speed was 80 mph. I have not used it in a match yet, not sure if I like to track each point since it can be distracing tapping my watch after each point. Anyone upgrade to the full version? I wonder how good the analytic is.