Tim,
When I look at your map, it APPEARS as though you are maybe 2' of height, within the flood zone. Is it possible that the floor of the improvements are that far above the ground? I've had this happen several times (I've also had "re-engineered" flood zones), and I won't change the report without a survey, with a flood determination, that I can include in the report.
BTW, we live on a hill, and there's a 50-55' drop from our back deck, to the back of the property, which is actually in a creek bed. Technically, part of our lot is in a flood zone. If our house gets flooded, you'll see the animals lining up 2x2...