Bid up suggestions

Hello everyone! Sorry, incoming long post. I’m planning my first Amtrak trip so I’ve been researching a bunch and trying to learn the tricks to winning a bid for a roomette. I noticed something while messing around with the tickets and I was hoping maybe someone could shed some light on it for me.

I’m planning a trip from VA to FL on the Silver Meteor. When I go to buy a ticket for 2 people, it says there are only 3 rooms available. When I change it to 6 adults, still, there are only 3 rooms available. But once I change it to 8 adults, all of a sudden there are 8 roomettes available to book. What’s the truth here?

I figured it was one of 2 things: either they lie about how many are available so you feel pressured to book the room outright instead of bidding up for it. Or, they offer those extra rooms at a higher price.

I was trying to gauge how many rooms were available to that I could place my bid accordingly. The price different between the lowest bid price and the instant upgrade is $500, so I’m trying to not put up more money than I have to.

Also, how many roomettes in total are there on this train? TIA!!!

TLDR; the app tells me a different number of rooms are available when I put in a different number of tickets. I’m trying to understand how many roomettes are actually available.