ask FNMA that, they don't care, just hold up the process and do it! This is about "finished area" not GLA. It looks like to me this only matters if there is a sloped ceiling unless I missed something.
Attics, Lofts and Low Ceilings Level ceilings must be at least 7 feet high, and at least 6 feet 4 inches under beams, ducts and other obstructions. There is no height restriction under stairs. If a room has a sloped ceiling, at least one-half of the finished floor area must have a ceiling height of at least 7 feet. Otherwise, omit the entire room from the floor area calculations. If a room with a sloped ceiling meets the one-half-of-floor-area-over-7-feet requirement, then include all the floor space with a ceiling height over 5 feet. Lofts and finished attics must be accessible by a conventional stairway or other access to be counted. If you can only reach the loft by climbing a ladder, it’s not part of the finished floor area regardless of the ceiling height.
Interesting, so only one of the rooms on the level has to be over 50% to count all of the level over 5 feet. Kind of weird, but ok.