@komivesg I have a Vortex too. Try this to get the Vortex closer overall:
- Set your tire pressure as normal
- Warmup your trainer 10 min endurance zone and 2 min high tempo should be enough
- Do a spindown calibration
- Check power from Vortex and Power Meter without Powermatch somewhere in Tempo zone. Power meter on Edge and Vortex on App for example
- If Vortex power is too high (higher then your Power Meter), add some tension on the roller by turning the trainer adjustment knob 1/4 turn counterclockwise
- If Vortex is lower then Power Meter release tension by turning the knob 1/4 turn clockwise
From there on, don’t do any spindown calibration anymore but just make sure you have the same tire pressure.
It will still not be perfect but much closer except for the first couple minutes of the session when the trainer is still cold.
Since i’ve done this, Powermatch corrects around 20W at the start (cold) and after about 5min, the correction is limited to a couple watts for all steady state intervals. For HIIT, you probably will still need to correct a bit by using Lap Avg as you do now.