I'm not sure about the ratings, but I can share my experience and my new resolution NEVER to own a house that requires flood insurance ever again.
In the late 70s, we bought a house in town that had a drainage ditch behind it. It was large, maybe 15ft deep and 30 yds across. It drained several streets to a river, which was 1/2 mile away. Mortgage required we have flood insurance. Survey showed the house was 21" above the 100 yr flood plane. Below 18" above the flood plane and you couldn't get the insurance and the mortgage company wouldn't lend money on it.
Flood insurance is sold by everyone, but it's really a federally offered program, and your rates are based on where you are in relation to the flood probability. So you can't go to 3 different agents and get a different price on the same house for flood ins.
We lived in that house for 10 yrs. The initial price was like $300 a yr. No biggie.
Over the next few yrs, the price crept up a little each yr, and was up to $1K per yr for several yrs.
Then our city did some re-figuring or the flood plane was updated or whatever, and as a result, our rate went to like $30/yr. GREAT!
Then there were several yrs of heavy flooding in the Southeast. Our agent sent us a ltr saying, "STAND BY, due to heavy sustained losses in the SE, everyone's insurance will take a drastic increase this year."
Our $30 premium went to like $600! I'm thankful that it had been lowered from before, and I'm more thankful that we've moved!
Ron