In addition to the debentures authorized by Sections 1001.1, 1001.7, and 1001.8, the department may issue additional debentures at any time pursuant to this chapter if the total amount of debentures outstanding at any time does not exceed the total amount of debentures authorized by this article.

Debentures which are refunded pursuant to Article 5 (commencing with Section 1004.1), or for which money or securities sufficient to pay the principal, interest, and any redemption premium thereon have been deposited in any reserve fund or in trust, are not debentures which are outstanding within the meaning of this section.