For the purposes of Clauses 76.4 and 76.5 above, if the Current Index has not been published prior to the due date for any interim Payment Certificate as stipulated in Clause 64.6 of the Conditions of Contract, the price adjustment in respect of that interim Payment Certificate will be provisionally calculated and added to or deducted from the sum payable in the interim Payment Certificate by the Engineer using the latest published MMPI and shall be corrected in subsequent interim Payment Certificate following the publishing of the Current Index.