There's really no basis for your argument for more compensation. The opportunity for you to negotiate has probably gone. If you want to stay at the same hotel, why not ask them simply to comp you a specific night/nights.
40K will buy you ten nights at some Hilton group hotels, certainly four nights at some Hiltons/Doubletrees. From what you say it will buy you two nights at the hotel you are focussed on if you're lucky with the dates: otherwise it simply makes a significant contribution to the points total required for the stay.
No harm in trying, of course, but be prepared to be rebuffed: going all out to exploit these situations is never going to be a comfortable process.