Interest on deposits under subpart F of part 842 of this chapter is compounded annually and accrued monthly.

(a) The initial interest on each monthly difference between the reduced annuity rate and the annuity rate actually paid equals the amount of the monthly difference times the difference between—

(1) One and six tenths raised to the power whose numerator is the number of months between the date when the monthly difference in annuity rates occurred and the date when the initial interest is computed and whose denominator is 12; and

(2) One.

(b) The total initial interest due is the sum of all of the initial interest on each monthly difference computed in accordance with paragraph (a) of this section.

(c) Additional interest on any uncollected balance will be compounded annually and accrued monthly. The additional interest due each month equals the remaining balance due times the difference between—

(1) One and six tenths raised to the 1⁄12 power; and

(2) One.