Originally Posted by the_traveler
I don't believe so.
It's just like you can buy a "C" bucket seat fare and a "C" bucket room fare, or a "B" bucket seat fare and a "C" bucket room fare, or a "B" bucket seat fare and a "B" bucket room fare. Each is independent of the other.
No, you can't do that. If you buy a room prior to boarding, regardless of what bucket the room price is in, the seat fare will always be the lowest bucket no matter what. Even if Amtrak never even sold that low bucket seat price because it was a holiday, you'll still get the lowest seat price
Turning to diesteldorf's question, I honestly don't know. It would certainly be easy enough for Amtrak to do so, simply by taking whatever the normal low bucket fare for the room is and subtracting from that the difference between the lowest coach fare and what was actually paid.
I suspect however, that Amtrak probably does not bother to deal with that, figuring that you already got the lowest price on the room so you are still ahead of the game.