Monthly allowances shall be adjusted annually for time commencing on April 1 and effective with the monthly allowance regularly payable on the first day of May beginning with May 1, 1969. The adjusted monthly allowance shall be equal to the base allowance multiplied by an adjustment factor which is equal to the ratio obtained by dividing the consumer price index for the immediately preceding year by the consumer price index for the recipient’s base year. The adjustments shall be subject to the conditions and limits provided in this article.