A November 2014 study of public building transformer loading by the State of Nevada confirms widely observed underloading of building transformers.   A recent case study is available at this link:

State of Nevada Powersmiths Baseline Transformer Report 05nov2014 (1)

To advance its advocacy for changes to Article 220, the University of Michigan will coordinate state-by-state proposals with the State of Nevada and other states to modify branch circuit and feeder design requirements.