As far as calling the game, I agree that it is the most important thing, and that part of the evaluation went well.
He told me to use preliminary signals for two reasons:
1) Sometimes I seemed like I was in a rush to get to the table, so he said by giving a preliminary signal, I would have to slow down and everything would go more smoothly.
2) He said that it is not one of those things that make or break an official, but it is one of the small things that may, down the road, help seperate me from other official(s).
I didn't know people got so passionate about preliminary signals.