The NEC's section 110.3(B) misinterpration is explained by Chris Coache of the NFPA here: | National Electrical Code

NEC 110.26(E) Dedicated Electrical Equipment Space. Service equipment, switchboards, and enclosed panelboards must have dedicated electrical equipment space and be protected from damage. (1) Indoors. Service equipment, switchboards, and panelboard enclosures indoors must comply with the following: (a) Equipment Space. The footprint space width and depth of the equipment of the dedicated electrical space extending from the floor to a height of 6 ft above the equipment or to the structural ceiling