Mississippi is a late comer to this game. As a result, they have some very twisted rules and rate schedules in place. The newer plans treat excess power and offset power differently than the old plans. The businessmen and lawyers have all the details clarified, classified, and inked out already. No matter what kind of customer you are or generation scheme you employ, they have it spelled out.
Mississippi gets a big fat F from these guys regarding their stance on solar:
https://solarpowerrocks.com/mississippi/