If I select one of my activities on Garmin Connect, click the gear icon, and select Set As PR, and choose Max Avg Power (20 min), it displays the Max Power value as the value to replace the previous record with... instead of the 20 min Max Avg Power... obviously there's a huge difference in these two values.
By the way, the 20 min value that Garmin Connect displays, when I upload the activity from my Edge 1000, is different than the value that the Edge itself indicates for the ride. So the Edge wants to set a record when the web site doesn't. Why is that?