The yield on a variable yield issue is computed separately for each computation period. The yield for each computation period is the discount rate that, when used in computing the present value as of the first day of the computation period of all the payments of principal and interest and fees for qualified guarantees that are attributable to the computation period, produces an amount equal to the present value, using the same discount rate, of the aggregate issue price (or deemed issue price, as determined in paragraph (c)(2)(iv) of this section) of the bonds of the issue as of the first day of the computation period. The yield on a variable yield bond is computed in the same manner as the yield on a variable yield issue. Except as provided in paragraph (c)(2) of this section, yield on any fixed yield bond in a variable yield issue is computed in the same manner as the yield on a fixed yield issue as provided in paragraph (b) of this section.