Thanks for the clarification. Ok, on a 5/1, at least 4.25% is possible - albeit tight, depending on your loan amount and the cost of the LPMI. The loan officer probably forfeited his or her paycheck . . . and might have had their next pay check hit for a deduction . . . but not by so much that they will be working free for 6 months. He or she will never make that mistake again, I can assure you.
If that number (the 4.25) was widely populated, then yes, someone should have seen it . . . but most underwriters and processors are coming off 6 months of 80 hour weeks due to the drop in rates, and EVERYONE is tired - even the most cautious are going to make a mistake now and then. As Bryan said, cost of doing business - and if it is possible (as it is with a 5/1 at the moment), they can and should honor the rate. . . . but it is an expensive mistake.
Depending on the way the institution is run, locking a rate is a very different process than doc'ing a loan. In my set up, for instance, I am pricing each loan live - there are hundreds of moving pieces and dozens of secondary market investors pricing pools of money. I am not simply going to a board, looking up, and saying "yup, the rate for the day is 4.5%" or whatever. In some institutions, the loan officers are one step removed from this and they are getting this information filtered from someone else at the lender - but someone is dealing with it. Banks do not simply lend out their own money and wait 30 years to get it back. They would run out of money if they did that - they'd have to take a 30 year vacation and come back and collect. They make loans, underwritten in many cases to the national standards of fannie mae, freddie mac, or FHA (HUD) . . . then they pool these loans together and sell many of them to secondary investors (who can afford to wait to get paid) for a premium so that they can recapture the money to relend. Sometimes they continue to do the work of "servicing" the loan - that is, collecting and applying payments - so it looks like you are paying them back directly - but in reality, only a small percentage of loans written by any institution is actually held in that institution until it is repaid in full. Some do not hold any at all.
SO . . . a few things happened here, most likely. The loan officer/institution is getting hit by an investor for failing to deliver a locked loan - locked at the wrong rate, or at the wrong price . . . the bank or lender is faced with the possiblity of having to hold your loan and not "reliquidize" by selling it . . . and no one is going to make any money for having done the loan - tough pills to swallow.
If the institution is honoring a rate .375% lower than it should have been, close and don't look back. You are getting heck of a deal.
As far as the three days . . .
Law states that on a REFI of your PRIMARY RESIDENCE you have three FULL BUSINESS days to cancel a loan BEFORE it can be recorded by the lender. This harkens back to days when sleazy sales/notary people would knock on unknowing customers doors and tell them that they had to sign or their house was in jeoprady. It is more of a blessing than a curse.
SO . . . if you close today . . . SATURDAY COUNTS (Sunday and Monday holiday do not) then Tuesday, Wednesday . . . first day that the loan could fund or record would be Thursday, by law.
If the bank is honoring today . . . someone is also paying a rate lock extension fee. . . . probably .01%-.03% of your loan amount each day . . .this is a real cost.
Sign away.