I have been using my Mag turbo at level 3 as per the Swift profile and I can’t is over 500W.
As I accelerate gently the watts build 100 -> 500 nicely and if a keep on accelerating maybe passed 30 mph the watt will drop or hover around 500.
Using trainer road this would be 600/700 and up to 1000 watt on a sprint!
But Swift will start to show the watt drop below 500.
My turbo is https://www.cycleops.com/product/mag