I think that bidding should be sent a bit differently root, in order of preference. For example, I wouldnt want dragon after bidding 11 points, but I could be okay with bidding on grass with 11, so I could send you
Dragon - 5
Grass - 10
(the rest)
Thus, if I dont win my dragon bid at 5, I could get my grass bid at 10, but only if I fail the dragon one.
It could be ruled out simply enough, IE in the event of a tie, whoever submitted their bid first win, and whenever possible, you are given your highest up choice, even if you win multiple bids