With a 100% of your theoretical downwash speed coming up at the rotor from underneath, you are in autorotation or as near as dammit, not VRS.
I have sat in autorotation in an updraught, as have many others, but suddenly getting a descent is due to variations in the strength of that updraught not VRS - although allowing the aircraft to descend in that configuration then pulling a handful of power to arrest the RoD might get you a lot closer.