Would you consider a parking structure attached to a hotel to be an attached garage?
The parking structure in question is at grade and does not have a door at the entrance.
So it's a carport? Is it just a roof scabbed on the side of the building to cover the cars? I wouldn't call that an attached garage.
It is a regular concrete parking structure with 5 levels.
I can see where that may be the nearest correct designation. What would hurt is if it went down about three stories. Other than some electrical wiring there might not be anything to get flooded, but, it could influence the rating on the entire hotel building.
Call the FEMA Map Information office at 877-336-2627. You should be able to get some sound advice.
That raises the question as to machinery that services the structure: Elevator motors, power boxes etc.