Doesn't surprise me to hear someone who has done many practice autos has problems with a real one.
The way I've seen autos taught is that it's a technique. That's not innacurate, but it is incomplete. The awareness of the helicopter's performance is as important as the technique.
When flying, you should always consider things like the weight, altitude, landing area altitude, etc. not just for flight performance but also in case of emergencies.
If you're very experienced at practicing, then that is the mind set you will be in when you do it for real.
When it comes down to it, the auto will save me and my pax and hopefully the airframe.