The Center property is used to adjust the mechanical starting point of the 0 position. Its range is 0 to 63 which provides an additional 180 degree adjustment to the Value property. It is also 2.8 degrees per step. This value is typically set to a value between 20 and 40 and must be customized for each servo. By adjusting the Center property, The 0-63 range of the Value property can be centered over the 180 degree range of the mechanical capability of the servo.
Every servo is different.
Even with the same manufacturer and model of servo, the mechanical capability may translate to a different area of the servo, so it is important to make this adjustment for each servo you use. When adjusting the Center Value to find the proper value, first set the Center property to 40 and the Value property to 0. Slowly move the Center property down until the actuator on the servo hits its mechanical stop. Then bring the Center property up by 1. The InvertOut property is used to reverse the direction that the servo will rotate in response to the Value and Center properties.