Cooperatives are governed differently
The Public Service Commission regulates Entergy Mississippi and Mississippi Power. Rural electric cooperatives are member-owned and governed by their own boards rather than by the Commission in the same way.
So the net metering rule, the Distributed Generation Benefits Adder and the low-to-moderate income adder are Commission arrangements applying to the regulated utilities, and a cooperative may take a different approach.
That can cut either way. A cooperative may compensate exports more generously than the Commission tariffs or less, may cap system sizes differently, and may charge different interconnection fees.
With roughly 20 cooperatives in the state, there is no single answer. Check the utility name on a recent bill, then take specific questions to that utility.
The questions worth putting in writing
Ask how exported electricity is compensated and at what rate, whether any adder applies, and whether that rate is fixed or reset periodically.
Ask whether generation is netted across a billing period or measured instantaneously, and whether excess credits carry forward or expire.
Ask whether credits can offset fixed charges on the bill or only energy charges. That distinction materially changes what a system saves and it is easy to overlook.
Ask what system size limits apply, what the interconnection application involves, what it costs, how long approval takes, and whether any solar-specific charge or minimum bill applies to customer generators.
Reconciling the quote with the answers
Ask which export arrangement the projection assumed and which retail rate it applied, then check both against what the cooperative told you and against a recent bill.
Ask what self-consumption share the model assumed. Under any arrangement where exports are worth less than retail, that assumption drives the savings figure.
Ask whether the installer has completed projects on your specific cooperative recently. Interconnection practice varies and recent local experience is what moves a project along.
If the quote cannot be reconciled with what the cooperative told you, ask for it to be rebuilt rather than explained. That discrepancy is the most useful thing you will find before signing.
What the arithmetic actually rests on
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase receives no federal tax credit, and Mississippi has no state solar tax credit.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.
Everything else comes from your own utility: the retail rate, export compensation, any adder, the netting method, whether credits offset fixed charges, size limits and interconnection.
Ask for the projection rebuilt from those answers, with your rate taken from a recent bill and any solar-specific charges included.