ESC Calibration issue

[photodude]

Describe the bug
Calibration of the ESCs does not behave as expected. In some ways the ESCs behave as though they are entering the programming mode as the beeps from the ESCs/motors sounds like the programming mode sounds

To Reproduce
Steps to reproduce the behavior:

1. open the calibration example sketch
2. run the calibration example sketch
3. listen to the beeps from the ESCs/motors

Expected behavior
ESC calibration should be simple and accurate, the ESCs should not behave like they are being reprogrammed.

Hardware (please complete the following information):

• Board: Mega
• I2C: Adafruit PCA9685 16-Channel Servo Drivers
• ESC: Aerostar RVS 40A Electronic Speed Controller w/Reverse Function 3A BEC (2~4S)
• Motors: SunnySky 980KV II
• Prop: 6040E/EP

Additional context
Issue could be the timing of the calibration delay and pulses, or something else.