I jumped on this old thread because I have been concerned about the 3 foot rule and a recent visit with my electrician informed me that we may be able to use the like for like rule. I had originally planned a new 200 Amp service panel to replace my 100 Amp Zinsco panel. Doing it this way will avoid the risk of an engineering study and a new service drop to accomodated moving the location of the service panel 3 feet further from the pole.........
At this point, I think I should be ok with like-for-like... it just took way more effort to get that assessment than I think is reasonable. Plus the delay pushed me out of the 2020 ITC so I lose 4% on the net purchase amount.