Think about it just a bit. If they counteroffered every offer that was too low with their lowest available room, wouldn't that kinda defeat the auction nature of the site? How long would it take for us to figure out and just make our first bid ridiculously low, and then take the counteroffer? Why not just show the prices for each star level, and let you choose? The reason why is that you will always pay more than the bottom rate in an auction. Your 100 GBP is more than the bottom rate (unless your prior bid was 99.99). And they would rather have that extra money in their pocket than yours.