(1) Any surviving spouse eligible for pension under this section shall, if such surviving spouse so elects, be paid pension at the rates prescribed by section
1541 of this title, and under the conditions (other than the service requirements) applicable to pension paid under that section to surviving spouses of veterans of a period of war. If pension is paid pursuant to such an election, the election shall be irrevocable.
(2) The Secretary shall pay each month to the surviving spouse of each Spanish-American War veteran who is receiving, or entitled to receive, pension based on a need of regular aid and attendance, whichever amount is greater
(A) that which is payable to such surviving spouse under subsections (a) and (b) of this section as increased by section
5441 of this title, as in effect on December 31, 1978; or
(B) that which is payable under section
1541 of this title, as in effect on December 31, 1978, as increased by such section
544,1 as in effect on such date, to a surviving spouse of a World War I veteran with the same annual income and corpus of estate. Each change in the amount of pension required by this paragraph shall be effective as of the first day of the month during which the facts of the particular case warrant such change, and shall be made without specific application therefor.