The NEC is very restrictive with wire amperages, where utilities get full range.
I know the utilities don't use the NEC for wire sizing. I went back again and finally saw the last footnote about the NEC table and now I understand why you mentioned it....thanks for clearing that up. I was reading the Southwire info as if it was an NEC table.
For my new service the POCO is supplying 4/0AL to the meter in conduit. 350mcm if I ask for 400 amp.