Thank you for the information, I am using the roboticape
servo commands on Beaglebone Blue which are expressed in a normalized manner between -1.5 = 600us to +1.5 = 2400us. I think think this might explain the discrepancy.
I've adjusted my code to send raw pulse widths (rc_send_servo_pulse_us) instead of normalized and it seems much closer to the numbers you describe.
Thanks for the help.