I have never seen a meter mounted directly at a padmounted transformer.
Could you get us pictures?
You seem to be describing a most unusual service. The CT zone within the big switch box going unused, since a separate meter and CT can will now be mounted at the pad. I find that set up hard to imagine.
Utility side arrangements are outside the scope of the NEC. Period. Their control extends up until the customer's first disconnecting means.
The meter's location does not change that.
Since there is no national code to tell the Poco what to do, they call their own shot. Out west the industry has banded together to form EUSERC, a standards committee.
I would log on to the utility website and poke around.
Even better, place a phone call. If you install anything they don't accept....
BTW the AHJ and Poco have long ago decided the turf war. You can ask either as to where they draw the line.
