Since a non-municipal POCO has the ability to set a standard for getting power hooked up, I guess you can say that the POCO is "responsible for enforcing the requirements of a code or standard."
But judging from the way these terms are used by everyone else on this forum, people tend to differentiate between the building department (AHJ) and the POCO. And in the informational note for "AHJ" in the NEC, none of the many examples given are POCOs.
With a municipal utility, I understand the building department and the POCO are the same entity, but it is still usually possible to differentiate between their actions as POCO and their actions as building department. Are they not different departments of the municipality?
Cheers, Wayne