The total cost can include all kinds of crazy fees. I'd get a book that's no more than a couple of years old so you know what's legit and what's negotiable both with the mortgage lender and with closing costs.
In answer to your original question, we've had a pleasant association with James B Nutter. Sometimes your own bank will be anxious to hold onto all of your business.
Also, there are different kinds of preapprovals, some of which are little more than a nice pat on the back and others that pretty much signal the seller that you are truly in a position to make an offer.