Servo rotation not symmetric

We applied +1.9% and -1.9% duty cycle PWM value for servo 1 to rotate from center to both right and left.
However, the rotation always looks a little bit overshooting on one side than the other.
We are using our own micro-controller to control the servo which is Atmega 2560.

Hi, Gary

For your problem, because you directly use the PWM signal to drive servo, so we suggest you to check the source code. The method we use to control servo motor of uarm is simply to use the library <Servo.h> in arduino library. You can check the original code in this library to see what PWM signal range they used to drive the servo.

The link below is the original source of servo.h