New to 2017 Code is the introduction of the use of 120/208 volt services into the residential service adjustment factors section. It has always been just for 120/240 volt services and they now allow us to use this adjustment for 120/208 services also. Only difference with the inclusion of the 120/208 services is that you can not down size the neutral conductor. it is definitely a welcome change to the Code.
Till next time be safe work safe, wear a mask.
Jake