Available construction proceeds do not include gross proceeds used to pay issuance costs financed by an issue, but do include earnings on such proceeds. Thus, an expenditure of gross proceeds of an issue for issuance costs does not count toward meeting the spending requirements. The expenditure of earnings on gross proceeds used to pay issuance costs does count toward meeting those requirements. If the spending requirements are met and the proceeds used to pay issuance costs are expended by the end of the fourth spending period, those proceeds and the earnings thereon are treated as having satisfied the rebate requirement.