Flying Fader Arduino doesn't do variable duty-cycle PWM, unlike Circuit Python version

[aspdigital]

(Refer to the Adafruit article)
Starting here: Flying_Fader_Arduino, in the go_to_position function starting at line 100:

void go_to_position(int new_position) {
  fader_pos = int(analogRead(fader) / 4);
  while (abs(fader_pos - new_position) > 4) {
   if (fader_pos > new_position) {
    speed = 2.25 * abs(fader_pos - new_position) / 256 + 0.2;
    speed = constrain(speed, -1.0, 1.0);
      if (speed > 0.0) {
        analogWrite(pwmA, 255);
        analogWrite(pwmB, 0);
      }
   }
   if (fader_pos < new_position) {
      speed = 2.25 * abs(fader_pos - new_position) / 256 - 0.2;
      speed = constrain(speed, -1.0, 1.0);
        if (speed > 0.0) {
          analogWrite(pwmA, 0);
          analogWrite(pwmB, 255);
        }
      }
      
    fader_pos = int(analogRead(fader) / 4);
    
  }
  analogWrite(pwmA, 0);
  analogWrite(pwmB, 0);
}

Looks to me like the duty cycle is always 100% when the fader is moving. The speed calculation is not really useful.

Compare to the Circuit Python version (starting at line 60):

def go_to_position(new_position):
    global fader_pos  # pylint: disable=global-statement
    fader_pos = int(fader.value//256)
    while abs(fader_pos - new_position) > 2 :
        if fader_pos > new_position :
            speed = 2.25 * abs(fader_pos - new_position) / 256 + 0.12
            speed = clamp(speed, -1.0, 1.0)
            motor1.throttle = speed
            led[0] = (fader_pos, 0, 0)

            if MIDI_DEMO:
                global fader_cc  # pylint: disable=global-statement
                fader_cc = int(fader_pos / 2)  # cc is 0-127
                midi.send(ControlChange(fader_cc_number, fader_cc))

        if fader_pos < new_position:
            speed = -2.25 * abs(fader_pos - new_position) / 256 - 0.12
            speed = clamp(speed, -1.0, 1.0)
            motor1.throttle = speed
            led[0] = (fader_pos, 0, 0)

            if MIDI_DEMO:
                fader_cc = int(fader_pos / 2)  # cc is 0-127
                midi.send(ControlChange(fader_cc_number, fader_cc))

        fader_pos = int(fader.value//256)
    motor1.throttle = None

Here we see the PWM duty cycle, which is the throttle member of the motor1 instance, being set to the (clamped) calculated speed.

Why the difference? A typo? Untested code? Just wondering.