The BFEs are minimum expected flood levels. Deeper flood levels are possible. Additionally, there are substantial flood insurance discounts for every additional foot above BFE (known as freeboard) is up to a maximum four feet.
Note: The current building code requires new and Substantially Improved buildings be elevated to BFE plus one-foot. This height is referred to as the Design Flood Elevation (DFE). By default, these buildings end up having a minimum one-foot of freeboard.