Dear Harry: I live in Philadelphia, and I will retire to Florida in November. I just made settlement on a newly constructed home in central Florida. When I applied for my mortgage in Florida, I made the mistake of going to just one bank, the one recommended by the builder. I put in a down payment of 20 percent, and took a mortgage for $178,400. I gave the bank $2,000 for a "float down" rate. They told me that this meant that my rate could go down with market rates if they were lower on the settlement date. I see rates advertised down there of 4.5 percent. They have given me a rate of 6.25. When I questioned this, they explained that new-construction rates were higher than the rates on existing homes. My FICO credit score is more than 800, so my credit is top-notch. What's going on here?

What Harry says: Those toads are taking advantage of you. There is often (but not always) a higher rate on new construction, but the spread on your loan is way out-of-line. Get a couple of brochures from local banks in Florida showing the lower rates, and approach the chief mortgage honcho at your bank with these in tow. Demand that they give you the going rate shown on your brochures. If they won't move, get a lawyer to help you. The interest difference with a 4.5 percent over the 30 years of your mortgage is more than $70,000. That's not a misprint; it's $70,000, so it pays to fight. *

Write Harry Gross c/o the Daily News, 400 N. Broad St., Philadelphia, PA 19130. Harry urges all his readers to give blood - contact the American Red Cross at 800-GIVE LIFE.