99.26. In the case described in subparagraph 4 of the first paragraph of section 99.25, the officer’s pension is reduced for its duration by 1/4 of 1% per month, computed for each month comprised between the date on which the pension is granted and the nearest date on which the pension would otherwise have been granted to him without actuarial reduction under subparagraph 1 or 2 of the first paragraph of that section.