If I have underground utility service to a 400 amp meter/main/dist service (such as Eaton HP40SH) mounted on the exterior of a residence in which there is distribution to 2-200 amp panels that are mounted indoors back-to-back with the service and protected by 200 amp circuit breakers at the outdoor panel, have I violated 225.30 by bringing multiple feeders to the building?
The Building is only being served by one service with a single service disconnect and that happens to be on the outside of that building, per 270.70(A)(1). If this was on a pedestal out in the yard you might have a question but you are simply talking about distribution within the building. IMHO
In fact you could run this inside with a single feeder and exploit 310.15(B)(6). I think you need to use 310.16 if it is 2 feeders.