Thanks,
squirrel. I suppose I've could have added it all up too, but following their exploded overall drawing and searching for all the details made my head ache. I just scaled the plan and the dimensions and ratio'd them and got two different answers -- either about an inch below or above 13.5 ft, so I guess you are correct. Or me.
Not that it really matters -- our room is 7 inches too short, and 1 or 2 feet too narrow. So be careful on your driving 'round those turns!
The official answer is probably "it depends on field conditions." If I ever left a dimension like that off a construction drawing I'd never hear the end of it!