I did not watch the video, and I'm surprised it's 1700FPM. That's more than a helicopter in autorotation pretty much.
But I can imagine that if the plane is properly suspended, any wind blowing might cause the airframe to fly, generating some measure of lift for less weight on the canopy?
I've flown a few Cirrus, but keep thinking about taking it to the ground, land on a road as you do in your Cessna.
