I have never taken auto's all the way to the ground with any of my students and after 1500 hrs instructing I have had a good few get their PPL H's, and yet they do an auto to the ground on their test and to a man or woman they all said it was straight forward. So if they can do it for real having only ever done auto's to the hover why put the machine at risk during trainning for no reason at all.
And people say that machines like the Bell 206 and Bell 47 are great machines to do it in and I would agree but get it wrong in a 206 and thats 500 grand you just wrought off.
You can drop an R22 from 5 to 10 feet without doing it or the people in it much harm so if a student can get the machine to a spot, flair and leval at about that height than why risk taking it to the ground.........