Room rates depend on the locale, events in town, etc. Hilton (and the other chains) rarely price to the customer -- they price to room availability.

My situation was reversed in NYC. I used to stay at the Marriott East Side, and have the status to reflect it. Problem was, their rates got too high and were sold out more than 2 weeks in advance. I found I was able to get better rates at the Waldorf and New York Hilton. I once called back the Marriott to see if they would match the Waldorf's rates. Main reservations, hotel reservations, the hotel manager, the conseirge manager who knew me personally all declined -- wouldn't even go down $20.