In both Mike Holt's and Stallcup's books the standard calculation for multifamily dwellings is performed using the demand factors of NEC Table 220.42 regardless of how many dwelling units are in the building. These demand factors are applied to all the dwelling units combined. The NEC is not very clear on whether NEC Table 220.42 should be applied on single or multifamily dwelling units. Except in Part IV, optional calculations, demand factors are applied to all the dwelling units combined in accordance with NEC Table 220.84. It seem's to me that NEC 220.42 should be applied in sizing the subfeeders of each dwelling unit and then the calculated load is added up to size the main feeder for the entire building. This would be the way I would do the calculation. Your thoughts on this?