eagle86
What is this "aerodynamic autorotation" you are talking about?
Autorotation is an aerodynamic effect. We call it "autorotation"
There is no other form of autorotation.
I have flown Seaking/Wessex/Gazelle/Squirrel/UH1/AB212/S70B/Mi17 and none of them require anything like the height you talk about even from OGE hover.
Yes from a hover you will lose significant height if you try to regain speed, but that is nothing to do with autorotation, that is just trading height for speed. Autorotation is very quick to take effect. Try an over aggressive fast-stop and watch how quick the Nr gets excited.