How do you switch off power control in iOS?

Unfortunately not. You can remove the trainer from the sensors and add your PM’s BT device if you happen to have a PM that supports BT.

Does this mean that the IOS app should control the trainer? I have tried the IOS app but the trainer is unaffected. Is there information anywhere on how to set this up?

I finally found this link with some setup information.
I also see that it won’t control the Neo.

The app description on the App Store also outlines which trainers are supported.