Set your servo time to .00087 and you should be good 
I have been running tests and it is working well for position. you need to have the latest software on everything.
I tried to set servo time to .00087 but it would not stay and reverted to last setting.
So I downloaded latest Plugin and it had a selection in the drop down of .00084 so tried that. Still not returning to zero.
Then I did a clean install of the latest Mach version R2.0.036 set up motors and estop again.
Now the gcode window and line count jump and it stalls around line 980 of the roadrunner.
Tried updating the plugin just in case it changed. Still the same.
Have the latest firmware. Mach version and plugin. Legacy mode turned off for USB
I think to save my frustration I will set this aside for now and watch for updates to come out.