An issue is treated as meeting the rebate requirement if --
(i) The gross proceeds (as modified by paragraph (c)(3) of this section) of the issue are allocated to expenditures for the governmental purposes of the issue within the 6-month period beginning on the issue date (the 6-month spending period); and
(ii) The rebate requirement is met for amounts not required to be spent within the 6-month spending period (excluding earnings on a bona fide debt service fund).