I'm a lender in the Sacramento area, I can help you analyze your expected returns, and various aquisition costs involved....
BTW - As of Apr of last year, there are no more upfront points charged by brokers, only the big retails companies can still do this (Wells, BofA, Citi, Chase, etc)....you CAN still pay discount points when buying down the rate. Unless the loan officer is being paid on a hourly basis (not typical), then our compensation is paid to us by the lender, 100% that it..
Re a website to analyze ROI, I don't of one offhand, but again can help you run numbers if you like!
Good luck and best regards, Jeff Marr
Alpine Mortgage Planning