Herin lies the issue.
The sensor is not counting pinion revolutions, it is counting the number of pinion teeth that go by. Look at the position of the sensor, it is located centered over the pinion teeth.
In order for the sensor to count pinion revolutions, there would have to be a feature on the pinion that only goes by the sensor once per revolution, and the sensor would have to be located over that feature.
There were pics posted somewhere looking into the sensor hole to show this clearly, I can not find them right now. Maybe someone has or can take pics of this.