What you are describing does not make sense.
To the best of my understanding, PowerMatch is only active in ERG mode. It should have no impact in Standard or Resistance Modes.
There are 3 modes for trainer control:
- Erg
- Resistance
- Standard.
I would suggest trying Resistance mode and retesting for the sake of comparison. When I use something other than Erg, I like Resistance better than Standard. Maybe that will resolve your issues?