SECTION 1.  Notwithstanding the provisions of section 4 of chapter 32 of the General Laws, as appearing in the 2004 Official Edition, the Massachusetts Retirement board is hereby authorized and directed to grant Dennis Otis creditable service for the years of 1964 to 1970, inclusive, during which he served within the Massachusetts National Guard; provided, however, that he shall pay into the annuity savings fund, in one sum or installments, as the board shall determine, an amount equal to the regular deductions which would have been deducted for said period together with regular deductions which would have been deducted for said period together with regular interest thereon.  Dennis Otis shall, in addition to his actual membership service, be entitled to credit for the portion of the creditable service which the total of his actual payments, together with regular interest thereon to the date such retirement becomes effective, bears to the total amount of what her payment, together with regular interest thereon, would have been had he made a payment in one sum on the effective date of his retirement.