In proceedings initiated by a regular, temporary, or new hospital rate application, the burden of proof of the reasonableness, equity, and lack of undue discrimination of the proposed rates shall rest with the hospital. In proceedings initiated by an application for an alternative method of rate determination, the burden of proof of the applicability of the alternative method of rate review to the hospital shall rest with the hospital. In proceedings initiated by an order for Commission review of established rates, the burden of proof of the reasonableness, equity, and lack of undue discrimination of the established rates under review shall rest with the hospital.