The fees established by Section 810.208 hereof have been established in part on estimated costs to construct PLDF in the calendar years 1980 and 1981. In December of each calendar year, beginning with December 1981, the Board of Supervisors shall review and adjust such fees. Said adjustment to be based upon any increase or decrease in costs of construction as determined by the Engineering News Record Cost of Construction Index published by McGraw-Hill Publishing Company, or any successor thereof. The index for the month of November shall be used for such adjustments. Fees adjusted in accordance herewith shall become effective as of January 1, 1982 and on each January 1 thereafter. However, the maximum amount of fee payable by a subdivider shall be calculated based on the fee rate in effect on the date that the tentative subdivision map or tentative parcel map application is filed with and the application fees paid to the County. If the Board of Supervisors does not review and adjust fees in December of 1981 or any subsequent December, the previously established fees shall remain in effect until such review has been conducted.