Hello,
With Oneshot125 selected and working, ESC refresh rate is 8 times faster than standard PWM.
If you look at the RC-Out log (mot 1 to 6 in my example), the working range is 125-250 instead of 1000-2000 PWM range. It is the way to know Oneshot125 is activated and working. With a Oneshot125 capable ESC, the ESC detect the Oneshot signal and work accordingly.
https://community.emlid.com/t/edge-navio2-oneshot125-differences/12540
As the refresh time is shorter, there are less possibility of ESC-Motor desynchronising, as with PWM and larger low RPM motors.
Oneshot 125 is working with latest arducopter version on my CUAV V5+ but no way to have it working with Navio2 or Edge since 3.6.x version.
Marc