Withdrawal when pension, annuity or benefit is less than minimum sum
13.  Where the pension, annuity or other benefit which a member receives on his retirement per month is less than the amount specified in regulation 14(1), the member shall on attaining the age of 60 years be entitled monthly —
(a)to withdraw from the minimum sum deposited in an approved bank or in his retirement account, an amount equal to the difference between the amount specified in regulation 14(1) and the amount of such pension, annuity or other benefit, as the case may be;
(b)to be paid from his approved annuity an amount equal to the difference between the amount specified in regulation 14(1) and the amount of such pension, annuity or other benefit, as the case may be, except that the Board may permit an insurer to pay the member a sum exceeding such difference if the Board is satisfied that the total amount payable under the pension, annuity or other benefit is sufficient to support payment of such a sum for the lifetime of the member.