That comes back to the SDS plan. Originally crews filled up the entire dining car and on a full train, offered 3 seating times. SDS changed all that, with the reduced crews they could no longer handle that mass decent upon the dining car. So we got the staggard seating schedule, where tables are all at various and different points in the meal, of seating X tables every 15 minutes.The part that always surprises me is how often the diner is only seated to about half of its capacity on trains that are nearly sold out. Maybe that's part of the reason why they're always losing money?
As I mentioned earlier I believe, Amtrak has been increasing crew sizes, and therefore increasing the X number seated at each interval. But still the base plan remains that you use the staggard seating schedule, not the old way of filling the entire car at once, even on a full train and with a full crew. That should be changed IMHO. If they have a nearly sold out train, 2 cooks, and 3 SA's on board, then they should just fill the diner and go for max capacity.
I will say that while it would help the bottom line with the extra revenue, the diner will still lose money no matter what. That has always been the case. The reason that the freight RR's tolerated the losses on the dining cars was that the alternative, having the train sit in the station for 3 or 4 hours while everyone ran to the Harvey House for a meal, creates too many other problems and expenses. The dining car solved that problem, and it gave the customer a better travel experience too.