For purposes of paragraph (h)(3)(i) of this section, the separate purposes of a prior issue include the refunded and unrefunded portions of the prior issue. Thus, the refunded and unrefunded portions are treated as separate issues under paragraph (h)(1) of this section. Those separate issues must satisfy the requirements of paragraphs (h) and (i) of this section. The refunded portion of the bonds of a prior issue is based on a fraction the numerator of which is the principal amount of the prior issue to be paid with proceeds of the refunding issue and the denominator of which is the outstanding principal amount of the bonds of the prior issue, each determined as of the issue date of the refunding issue. (See also paragraph (b)(2) of this section.)