(2) The commission may provide that such bonds mature not more than 40 years from date of their issue and may provide that such bonds also be made payable from any otherwise unpledged revenues which may be derived from the ownership or operation of any sports and convention facilities. The commission shall also have the power to advance refund bonds issued hereunder in accordance with the laws of Oregon.
(3) The commission may include in the principal amount of any bonds issued to finance a sports and convention facility an amount for engineering, architectural, planning, financial, legal and other services and charges incident to the acquisition or construction of sports and convention facilities, an amount to establish necessary reserves and an amount necessary for interest during the period of construction of any facilities to be financed from the proceeds of such issue plus six months. [1985 c.654 §6]