(a) Description. This recomputation serves as a reduction in the PIA for entitlement to a periodic pension based, in part or in whole, on earnings after 1956 not covered under either the Social Security Act or the Railroad Retirement Act. A recomputation for a periodic pension is made in accordance with sections 215(a)(7) and 215(f)(9) of the Social Security Act. A recomputation affecting the Retirement Tier I, Overall Minimum, or Residual Lump-Sum PIA is required when all the following conditions exist—

(1) The employee has less than 30 years of coverage as defined in section 215(a) of the Social Security Act. The years of coverage include railroad and social security earnings;

(2) The employee becomes eligible for an annuity after 1985; and

(3) The employee becomes eligible for the periodic pension payments after 1985 based, in part or in whole, on earnings after 1956 not covered under either the Social Security Act or the Railroad Retirement Act.

(b) Effective date of recomputation. The Retirement Tier I, Overall Minimum or Residual Lump-Sum PIA is recomputed when the employee becomes eligible for a periodic pension payment based on other than railroad or social security earnings. However, payment of the recomputed PIA is effective with the month in which the employee becomes entitled to the periodic pension.