HC:
Well, if I had said "DUMP COLLECTIVE" we'd be having a different conversation. I did say "control Nr" which may mean lower the collective a little or a lot or to the bottom, whatever it takes (your eyes going to Nr in parallel, not in serial) and likely your cyclic probably giving slightly aft pressure, as you don't want to dump the nose ... anyhoo, let's not argue with what someone didn't say, alright?
Pete:
Move the controls first, and THEN do the troubleshooting
We are in violent agreement.
HC:
The core point on keeping the head loaded, versus unloading it, seems to be the core point of agrement, about which the disagreement seems to go round and round. If one delays lowering the collective (be it a little or a lot) and thus keeping pitch on the blades, the decay of Nr seems a foregone conclusion.
Pete:
Collective full down, with an Nr above the stalled Nr, I would expect to see Nr stabilize at the rigged Nr when descending at the usual autorotational airspeed (a range of values for any helicopter).
And as HC repeats what I raised earlier, we seem to actually be in violent agreement: you don't move the controls independently of one another, you tend to work them together ... and keep the lead loaded so it will perform as you more or less expect it to in re its autorotatoinal properties.
What Pete's short summary on those mishaps points to is people unloading the head in a hurry and perhaps not realizing that they are unloading the head ... and thus changing the nature of the airflow and AoA through the rotor system.
I note in your latest, Pete, that you have refined your point to a particular regime of flying where there is not a lot of stored energy in terms of arispeed to trade for Nr. With your crusade aimed at a particular flight regime, and given what else you have shared, it makes it clearer what informs your concerns in the first place.
Bombing along at max range airspeed (and with a lot of knots to trade for Nr) is a different case, though perhaps the Mosby crash serves as ample warning that one cannot be complacent.
HC
maybe 10 years ago max, S76 was being operated GoM without
any concept of OEI performance. Not sure if LW has caught up with that concept - seems not from his postings.
You lot were a couple of decades late to the show, seems to me. 
As I don't fly, nor ever flew the S76, why was that crap tossed at me?
In the twin engine helicopters I flew, we had separate performance charts for SE operations. SEAS was a critical T/O (reaching and passing) and Approach (going below) call out in the cockpit. Gee, I wonder why we did that, flying off of small deck ships. Care to share your pet theories? (Where is a sarcasm smiley when you need one?) We also had to practice, over and over, single engine landings to a spot at constant descent angle. Gee, I wonder why we did that? 
Started for me in about 1982.