IMO, the key learning in an AOW class is how fast you go through your air. I can explain the math to you, but experiencing it is an entirely different thing. More importantly, what you discover is individual issues. Here are two examples.
In the first two AOW dives, Diver A had show a tendency to go through his air pretty quickly. We calculated his SAC rate, and decided it was pretty high. Prior to the deep dive, we set up a careful multi-level plan that called for ascents based on when he or his buddy hit certain PSI levels. He hit those planned ascent levels so quickly it was astounding. He finished the dive with 400 PSI in his AL 80. I was not using an AL 80, but if I had been, I would have finished with 2200 PSI, and I am not some kind of diving superman. What was his primary learning from that dive? He had no business doing a dive like that without more training, practice, and a bigger tank. If he had just done that dive without being in a class, who knows what would have happened?
The second example is Dive B, an extreme athlete,competing at the very highest level in his primary sport. He cruised though earlier stuff, and he had a SAC rate to write home about on his AOW dives. Then he did the deep dive specialty. When we went to 130 feet, he turned into a totally different person. His eyes bugged wide. His SAC rate went through the roof. We had to end the dive very, very early.
Those are the things you need to learn when preparing for deep dives. Colors? Seriously--who cares?