133.2. The actuarial value of the additional benefits referred to in section 133.1 and pertaining to the years and parts of a year referred to in paragraphs 1 to 3 of section 73.1 and in respect of which benefits were obtained on 31 December 1999 shall be established within six months of the filing of the actuarial valuation provided for in section 174 on the basis of the data finalized on 31 December 1999. The actuarial value shall be established on the basis of the assumptions used in that valuation and bear interest from 1 January 2000.