133.3. 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 acquired after 31 December 1999 shall be established on 1 January of each year in which the benefits are acquired. Each of the actuarial values shall be computed during the year following the year in which the benefits were acquired, on the basis of the assumptions used in the actuarial valuation filed under section 174 and available before the end of the year of the computation. Each of the actuarial values shall bear interest from 1 January of the year in which the benefits were acquired.