The increases provided by section 1, when added to the annuities of retired civilian members of the teaching staff of the United States Naval Academy or the United States Naval Postgraduate School, do not increase the annuities of their survivors. The annuity of any such survivor, however, who is entitled to or becomes entitled to an annuity under chapter 607 [now 857] of title 10, United States Code, shall be increased in accordance with the following schedule:
“If annuity commences between—Portion of annuity not in excess of $1,500 shall be increased by—Portion of annuity in excess of $1,500 shall be increased by—
per centumper centum
Jan. 16, 1936, and June 30, 1955128
July 1, 1955, and Dec. 31, 1955107
Jan. 1, 1956, and June 30, 195686
July 1, 1956, and Dec. 31, 195664
Jan. 1, 1957, and June 30, 195742
July 1, 1957, and Dec. 31, 195721