Just to clarify, you're automatically getting that 25% discount because you're booking at least 14 days in advance. If you were booking less than 14 days out, you'd see a higher base fare and and a 10% discount with AAA, etc.

Tickets purchased with the 14-day advance purchase discount are still fully refundable (contrary to what may be stated on Amtrak's website) as long as you haven't yet printed your tickets, so it's usually best to book as early as possible and then wait until your day of travel to print them at the station. If you book online and your plans change before your travel date, you can cancel online and get a full refund to your credit card.