As described in Part 1643, Financing, the issuance of housing bonds by the State is entirely within the discretion of the State Comptroller. Bonds may, therefore, be issued by the State prior to the date of substantial completion, or subsequent thereto. The issuance of bonds simultaneously with substantial completion will, ordinarily, be fortuitous. The date of substantial completion has an important bearing on the debt service on the bond issue, as it not only controls the apportionment of the interest charge to development and operations, but also the provision for amortization. Prior to the date of substantial completion, debt service on the bond issue is limited to the provision of interest only. Subsequent to the date of substantial completion, the debt service will include a provision for amortization of the indebtedness, as well as the provision for interest.