6. An officer to whom paragraph 1 applies may elect to pay to the Board a sum equal to the amount of his award by way of repayment of his aggregate pension contributions under regulation B6 of the 1988 Regulations and to reckon as pensionable service for the purposes of these Regulations the pensionable service he was entitled to reckon under the 1988 Regulations at the time of his retirement with an entitlement to the award.