If the commission takes final action under N.H. Rev. Stat. § 362-C:3 or N.H. Rev. Stat. § 362-C:5 to approve the agreement and to fix the rates for Public Service Company of New Hampshire or its successor in the manner prescribed in the agreement, or to approve and implement an alternative reorganization plan, or both, the commission shall not thereafter issue any order or process which would alter, amend, suspend, annul, set aside or otherwise modify such approval or result in the fixing of rates other than in the manner prescribed in the agreement or the approved alternative reorganization plan.