I felt this way the last time I used it with DD2. I primarily used it as a method to fall asleep. I felt that it still helped me in labor because (to me) the main goal of Hypnobabies was to relax. Now, obviously, I didn't sleep through my labor, but it did help to put me in the relaxation zone.
The only one I'd make sure that you've done the whole way through without sleeping is enough to understand what the "finger drop" technique and the light switch are supposed to do, but even if you miss out on that, it's still no BIG deal. I've just found it more helpful this time around to understand what the hell Kerri meant by the finger drop technique since I always fell asleep before I got to that part when I was pregnant with DD2.