Bid Up for Sleeper room

[Nora17]

I reserved a roomette and am considering bidding on a bedroom. Is the bid I place in in place of the original price charged, or is an incremental amount added to the original roomette price? Also, on the AutoTrain I am assuming the bid excludes the Car reservation & price. Anyone know the answers to these questions?

 

[Exvalley]

It is an extra charge on top of everything you have already paid.