Same PM Different Readings

I am using a Stages single sided power meter with the bike on a Kickr. The Kickr is being controlled by the Wahoo app and I record the workout on it as well as on a Garmin 530 head. The Wahoo and the Garmin are both paired and using the data from the Stages PM but they are not in agreement. Yesterday I was doing a workout that had a 5 min threshold set and there was an 13 watt difference between the two. With the Wahoo reading higher than the Garmin. In the past I have attributed this to the Garmin suffering from PM dropouts.

Any thoughts?



Am I understanding correctly that both the wahoo app and the garmin 530 are recording power from the stages and neither is recording the kickr? So the wahoo app is doing a sort of powermatch by controlling the kickr but using and recording the power reading from the stages? My first guess is that this is not what is actually happening and the wahoo app is recording the kickr power and the garmin is recording the stages power.

I am not running the Kickr in ERG mode. I am just using the LVL controller on the app and shifting gears to control resistance.

I think you may be correct.