Buying an Amtrak ticket

Buying an Amtrak ticket.

The website tells me:

Amtrak offers discounts on most itineraries to cardholders of the following Amtrak partner organizations:

AAA (American Automobile Association)

Excellent!, I think. I'm a member of AAA. I select the menu item to request the AAA discount and click on the "apply discounts" button.

An alert box pops up:

A Passenger Discount has resulted in a higher fare than originally quoted

And I see it has.

o.O

I... guess I won't be requesting the AAA discount after all.