I'm sorry, but on the Auto Train (AT) that is not correct. It is true on all other Amtrak trains, but not the AT. On the AT, there is one dining car for sleeping passengers and at least one, sometimes two for coach passengers. The menu is different in the diner for sleeping car pax from what is served in the coach diner(s). It's not horribly different, but usually the quality is better in the diner for the sleeping car.
For example the coach dining car might offer strip steak as an entree, while the sleeper might get filet mignon medallions as an entree. Additionally as one other poster mentioned, in coach the wine comes in a carafe and is of a cheaper brand. In the sleeper's diner, they pour the wine directly from the bottle and you have your choice of red or white. (If you really like the wine, they'll even sell you a bottle if they have any left.)
Seating times are simply based upon the passenger load and how many dining cars are on the train. I've seen three seatings in the Sleeper's diner before, although many times they do manage to squeeze it into two seatings.
To the OP, you don't have direct control over the A/C in your room, as in temp setting or fan speed. You can however close the damper on the A/C vent to lesson the flow into your room. Additionaly there are defelectors that can be used to help keep the A/C from blowing directly onto you either while in bed or while seated.
Finally, you might find
these hints and tips from On Track On Line to be helpful. They'll give you a very good idea of what to expect from your travels on the Auto Train.
I hope that I'm not too late with my advice here, but I just got back from a cross-country Amtrak trip.
