Latest update brought this
Watopia 12/30 (v1.0.9318)
“When in workout mode, paired to a smart trainer, and you have ERG mode disabled you can now control your smart trainers resistance using the phone app. Again two of the blue buttons on Zwift Mobile Link will change to more & less resistance buttons. You can also use the + and - keys on your keyboard if you’d prefer.”
I am on a Tacx NEO and I would like to know how I can disable ERG mode while I am in a workout an control my resistance via mobiel app “two blue resistance buttons” or the “+” “-” keys on keyboard!
Thx for a short explanation!
I can’t even see an option for ERG mode, where is it. Plus the resistance is far to high on my Elite RealPower trainer, can’t do any recovery or low Z2 rides without the cadence being <70 and in granny gear, so I would like to know the answer to this as well.
ERG Power can be turned on/off in the workout Editor while planing and before you start the workout! But only if you have a Smart Trainer witch is able to do ERG Mode like NEO and Kickr. I doubt the Elite RealPower Trainer is Smart!
My question is, if there is an option to turn on/off ERG to SIM and back while you are right in an workout session!
Hello everybody!
If you are on a smart trainer that is ERG enabled, and would like to disable it, there is a selector on the workout menu just above the ‘Workout’ button labeled ‘Use ERG mode’ - deselect it to give yourself a flat resistance during the workout. If you do not see this option, your trainer is not ERG enabled.
To adjust the resistance in a workout when not using ERG mode, select the workout and start riding. Once the workout has been started, there are two ways to adjust your resistance. First, you can use the Zwift Mobile Link app - four workout specific buttons appear on the actions screen when a workout is active (pause, skip block, and the two resistance adjusters). Alternately, you can use the ‘+’ or ‘-’ keys on your keyboard to adjust the resistance. When you adjust the resistance, a bar will appear to the right side of your workout HUD that shows your relative resistance level. The lowest setting is equal to flat road, while the highest is around an 8% grade.
And finally, the Elite RealPower is a smart trainer, and it is possible to create a workout that uses both ERG and SIM mode in its duration - the free ride block in workouts use SIM mode! However, it does not follow the gradient of the course, but rather gives the adjustable flat resistance that non-ERG workouts use. We currently have no plans for allowing a user to switch between the two while working out, but with the workout editor it would be possible to build a custom workout which utilizes both modes.
I hope this helped! Ride on!
Thank you, I tried the “+” “-” key yesterday and the day before it worked a treat, up one from totally off had me at a cadence of 92 - 95 and 150 watts recovery on my Elite so happy with this now. 
I just press the + key a few times when I want more resistance to achieve 220w plus without going over 105+ rpm or if I want to do a power interval at low rpm.