When I quit I didn't do it with the help of hypnosis, but since have learned self hypnosis and understand pretty much how hypnosis works.

If in fact he has an  80% success rate, that's better than pretty good. The 20% were probably people who's lifestyle interfered with with the process. If you go to the clubs every night where smoke is all around you, and drinks that weaken your resolve it can defeat you.

I would like an 80% success rate in everything I do.

I would say go for it keeping in mind that you have to do your part 100% 0f the time. Think of smoking? Take in as much free oxygen as you can. go for walks, etc.