Hi Fritz
You don’t need to log two workouts; If you have a training peak account linked, you can view it in the analysis tab. You can see the details in the video: https://www.youtube.com/watch?v=30XDAtkDZ78
Note: one hour is the recommended time for the Aet Drift test and shouldn’t include warmup. I usually do a 1 hour 20 mins workout for the AET test and analyze the last 60 mins BPM to calculate the AET.