Can the rates be negotiated? Perhaps, if the new rate isn't set/hasn't taken effect yet. If you can find a real person who will sit down and talk to you like an adult, it may very well be possible to present a case to them that would lower the rate. Negotiation relies heavily on the amount of preparation you do before sitting down to talk, as you should not expect to get something for nothing. Having a backup offer (from another lender) may be a strong position to argue, but don't discount the security of your regular payment history since you need to convince them that you can both "win" from this negotiation.
My uncle once negotiated THOUSANDS off the price of a car, but it took him 8 hours to do so. It sounds kind of crazy to spend 8 hours with a car dealer, but he calculated that he earned a couple hundred dollars per hour by doing so, more than he made at work.
Read my 'fiscal fitness' financial disclosures here.