Pending their use in accordance with this subtitle, proceeds of bonds issued under § 10-331 of this subtitle may be invested in: obligations of or guaranteed by the United States; or certificates of deposit or time deposits secured by obligations of or guaranteed by the United States. Bond proceeds placed in escrow under subsection (a) of this section shall mature at such time or times as the Authority considers appropriate to assure the prompt payment of principal, interest, and redemption premium, if any, on the bonds that are to be refunded. The instruments in which the Authority invests proceeds of bonds issued for all or part of the cost of improvement or acquisition of a project shall mature soon enough to pay the cost of the improvement or acquisition. The Authority may apply the interest, income, and profit from the investments described in subsection (a) of this section: to pay the bonds that are to be refunded; or to pay the costs of acquiring or improving a project. After the terms of escrow are satisfied, the balance of the refunding bond proceeds, interest, income, and profit, if any, may be returned to the Authority for use by it in any lawful manner.