The amounts provided in paragraph (1) of subsection (a) of Code Section 15-9-63 and Code Section 15-9-64, as increased by paragraph (2) of subsection (a) of Code Section 15-9-63, shall be increased by multiplying said amounts by the percentage which equals 5 percent times the number of completed four-year terms of office served by any judge of a probate court after December 31, 1976, effective the first day of January following the completion of each such period of service. This Code section shall not be construed to affect any local legislation except where the local legislation provides for a salary lower than the salary provided in Code Sections 15-9-63, 15-9-64, this Code section, and Code Sections 15-9-66 and 15-9-67, in which event Code Sections 15-9-63, 15-9-64, this Code section, and Code Sections 15-9-66 and 15-9-67 shall prevail.