Any retired full-time justice of the supreme, superior, district, or probate court who serves after retirement as a senior active status justice or a judicial referee shall be allowed his or her expenses and a per diem compensation determined by the supreme court upon recommendation by the judicial branch administrative council and based on the daily equivalent of the annual salary the retired justice would then be earning pursuant to N.H. Rev. Stat. § 491-A:1; provided however, that in any calendar year the total of the service retirement benefits that the retired justice receives pursuant to N.H. Rev. Stat. § 100-C:5 plus the compensation provided by this section shall not exceed the annual salary the retired justice would then be earning pursuant to N.H. Rev. Stat. § 491-A:1.