Yes, KickrV5 is +/-1%, Quarq is +/-1,5% and 4iiii is +/-1%.
There are a lot of opinions about what those tolerance really mean.
To quote Wahoo:
"Be aware that no two power meters give exactly the same reading. Multiple identical, simultaneously broadcasting power meters have been empirically proven to report different power numbers during the same workout.
Factors responsible for this difference include:
-Data transmission rate
-Power Meter or strain gauge location (example: the KICKR measures power at the hub, which will result in a lower power reading due to drive train power loss compared to a crank or pedal based PM)
-Differences during calibration
Additionally, consider that the KICKR power accuracy tolerances combine with your other power meters tolerance. This means that if your KICKR is rated to report +/- 2% accuracy and your power meter is rated to report +/- 3%, your total combined accuracy tolerance will be +/- 5% at any given time."
So when Wahoo says tolerance is additional to all the factors above, I really dont see why they would give a tolerance number at all (of course they must because of marketing), but it will have no practical meaning. Imo the +/-% given for trainer and PM is supposed to cover all the factors above except drivetrain-loss. In a perfect world, crank/pedal-based PMs should read a bit (2-4%?) higher than a trainer due to drivetrain loss.
So basically Im fine with my PMs reading higher than trainer, but imo 3-5% drift is not within tolerance. I told this to Wahoo after getting the answer above, but I got no new answer. They only set “request status” to solved.
I’m coming from a Neo 2T, my PMs read a bit higher than the Neo aswell, but there was no drift at all. But the Neo had brake-rub and people didnt know what would happen to support after Garmin bought Tacx, so when reading all these nice things about the KickrV5, I switched when I got a good deal. I also liked the feel of the Kickr18 better than Neo2/2T.
The KickrV5 was perfect on paper for me, auto-calibrating (didnt realize atm that the calibration needed coasting), great frame-compability and no front-wheel block. I must say Im dissapointed though. I genuinely belive there is something wrong with my KickrV5, since it shows two consistent, but different behaviours in ERG/sim-mode. But I really think there is no chance that Wahoo will admit this or help in any matter.