Each judge or special trial judge electing under subsection (b) shall deposit, with interest at 4 percent per annum to December 31, 1947, and 3 percent per annum thereafter, compounded on December 31 of each year, to the credit of the survivors annuity fund, a sum equal to 3.5 percent of his judge’s or special trial judge’s salary and of his basic salary, pay, or compensation for service as a Senator, Representative, Delegate, or Resident Commissioner in Congress, and for any other civilian service within the purview of section
8332 of title
5 of the United States Code. Each such judge or special trial judge may elect to make such deposits in installments during the continuance of his service as a judge or special trial judge in such amount and under such conditions as may be determined in each instance by the chief judge. Notwithstanding the failure of a judge or special trial judge to make such deposit, credit shall be allowed for the service rendered, but the annuity of the surviving spouse of such judge or special trial judge shall be reduced by an amount equal to 10 percent of the amount of such deposit, computed as of the date of the death of such judge or special trial judge, unless such surviving spouse shall elect to eliminate such service entirely from credit under subsection (n), except that no deposit shall be required from a judge or special trial judge for any year with respect to which deductions from his salary were actually made under the civil service retirement laws and no deposit shall be required for any honorable service in the Army, Navy, Air Force, Marine Corps, or Coast Guard of the United States.