Amtrak gives
15% off the lowest available rail fare to those 62 and older.
Note that the charge for a sleeper berth includes a rail fare for each person that the 15% discount is applied to, but not to the cost of the sleeper berth itself.
There is just 1 charge for the sleeper berth.
For instance. I travel by myself so I pay for the sleeper and 1 rail fare.
Two people share the cost of a Roomette or Bedroom and pay 2 rail fares.
It might also be worth noting that 3 people can occupy a Bedroom - 1 sleeper charge and 3 rail fares..
Also meals are included with the sleeper charge for however many rail fares there are in the reservation.
One of the east coast long distance trains does
not include meals with a sleeper (Silver Star).
Rail fare and sleeper pricing is yield managed.
Prices go up as the the train gets booked with reservations.
However many people's plans change and they cancel their reservation(s). That makes day to day pricing fluctuates according to demand.
As a general rule, the closer to the date you want to travel you make reservations the higher the pricing will be.
I try to book my train trips at least 6 months in advance and schedule my train trips during
Amtrak Guest Rewards Spring/Fall Double Days promotions so I get double AGR points.
Time joining AGR so you get some bonus points - usually 500 points if you travel within 90 days of joining.
You can book your reservation well in advance and join AGR within the 90 days of your travel date.