All assets heretofore or hereafter transferred to the Authority from the Literary Fund pursuant to § 22.1-175 shall remain assets of the Literary Fund and shall be repaid to the Literary Fund pursuant to this section but, until so repaid, may be used for all purposes by the Authority to the same extent as if such assets were the sole property of the Authority. On or before January 10 in each year the Authority shall set aside and repay to the Literary Fund an amount equal to the excess of the principal and interest collected by the Authority in the preceding year on account of obligations transferred to the Authority from the Literary Fund over such portion of such principal and interest as shall have been pledged by any trust indenture or resolution authorizing bonds of the Authority. The principal collected by the Authority on account of obligations transferred to the Authority from the Literary Fund shall remain part of the principal of the Literary Fund subject to the provisions of Article VIII, Section 8 of the Constitution of Virginia and of this chapter, and the interest collected by the Authority on account of such obligations shall be deemed to be interest on the Literary Fund subject to the provisions of Article VIII, Section 8 of the Constitution of Virginia and of this chapter; provided, however, that any such collected principal and interest pledged by any trust indenture or resolution authorizing bonds of the Authority shall continue to be held by the Authority until no longer so required by the terms of such trust indenture or resolution; and further provided that, on the next succeeding tenth day of January, any amount of such collected principal and interest no longer required to be held by the Authority shall be set aside and repaid to the Literary Fund as if it had been collected at the time it became no longer required to be held.