(a) Increase in family group. If an overall minimum rate is adjusted for the family maximum and an additional family member can be included, the benefits payable to previous auxiliary beneficiaries (spouse and children) are reduced to provide a share for the new family member. The difference between the Overall Minimum PIA (see § 225.15 of this part) and the family maximum amount is divided by the increased number of auxiliary beneficiaries. If the amount of each benefit is not a multiple of $0.10, it is rounded to the next lower multiple of $0.10. After determining a beneficiary's share (the amount after reduction for other benefits) the amount is rounded to the next lowest multiple of $1.00, if it is not already a multiple of $1.00.

(b) Decrease in family group. If an overall minimum rate is adjusted for the family maximum and there is a decrease in the number of eligible family members, the benefits for the remaining auxiliary beneficiaries (spouse and children) are increased. If the family maximum still applies, the difference between the Overall Minimum PIA and the family maximum amount is divided by the number of remaining auxiliary beneficiaries. If the amount of each benefit is not a multiple of $0.10, it is rounded to the next lower multiple of $0.10. After determining the beneficiary's share (the amount after reduction for other benefits) the amount is rounded to the next lowest multiple of $1.00, if it is not already a multiple of $1.00.

(c) Effective date of rate change. The overall minimum rate changes described in paragraphs (a) and (b) of this section are effective the month in which the number of auxiliary beneficiaries changes.