Workout and Elite DRIVO trainer don't work


I often do workout in NO ERG MODE with my Elite drivo trainer. I fix the resistance to only use my shifter to reach the right power. 

The resistance always move and it is impossible to do the workout. At the same cadence and shifter, the power pass to 370 to 550w. 

It is painful because i want to use zwift with workout. 

With ERG MODE activate is worst. 

please work hard to fix this problem. 

When i join an event, zwift and my trainer work well.

Everything update, my mac OS sierra and zwift.

Garmin express don’t work.