(a) The proceeds from the sale of any bonds issued under authority of this chapter shall be applied only for the purpose for which the bonds were issued; provided, however, that any accrued interest and premium received in any such sale shall be applied to the payment of the principal of or the interest on the bonds sold; provided further, that if for any reason any portion of such proceeds shall not be needed for the purpose for which the bonds were issued, then such unneeded portion of said proceeds shall be applied to the payment of the principal of or the interest on said bonds.
(b) The cost of acquiring any project, which shall be paid from the proceeds derived from the sale of bonds, shall be deemed to include the following:
(1) The actual cost of the construction of any part of a project which may be constructed, including architect's and engineer's fees;
(2) The purchase price of any part of a project that may be acquired by purchase;
(3) All expenses in connection with the authorization, sale and issuance of the bonds to finance such acquisition; and
(4) The interest on such bonds for a reasonable time prior to construction, during construction and for a period not exceeding six months after completion of construction.