Have tested auto's on such conditions many times and an auto from a 100ft or 200ft hover isn't a funny thing and it should not be recommended to train! Dead mans area on the hv-chart is the purpose of many chrashes.
The discussion shows lacks of aerodynamic background.
After initiating an auto (after engine failure) it needs 2-10 seconds to establish the autorotive airflow on the blades and the rpm is decreasing meanwhile. During the stabilized auto the rpm is ok, but the sinking rate is very high especially on low airspeeds. To high for a safe touchdown with only the rotor inertia! Therefore you need some speed for a flare.
Additionally to the "normal" problems- hold or increase RPM and get some speed for a flare- on the "two bladers" like 206 or other Bell helicopters it's easy to see mast bumping. Dropping down the pitch for RPM and pushing forward the stick to get some speed ends in negative g's! Pushing the stick forward drops down the rpm more than you think and without speed it's not possible to reestablish a good RPM. On a real engine failure in hover you could see a very strong a/c reaction and the ship turns to the left or right side (depends on rotor turning directions) while going down.
It's easy to impress a student with that kind of "flights" and the engine is running and you are prepared to react. But in the real business it's better to try to stay out of shaded hv area or only to stay there for a limited time.
It's not absolutely impossible to auto from shaded area, but it's very dangerous and the shortest way to bend the ship. I'm shure your insurance company is very lucky to pay for a ship bended by training flights in the shaded area!
