California Code, Government Code - GOV § 25531

Before accepting any written proposal, the board shall call for oral bids.  If, upon the call for oral bidding, any responsible person offers to purchase the property or to lease the property, as the case may be, upon the terms and conditions specified in the resolution, for a price or rental exceeding by at least 5 percent, the highest written proposal which is made by a responsible person, such highest oral bid shall be finally accepted.  In determining which is the highest oral bid the board shall not subtract therefrom any commission to be allowed to a licensed real estate broker, stated in or with the oral bid, but the board shall allow a commission at the rate specified in the resolution, as prescribed by Section 25527.  Such commission shall not exceed one-half the difference between the highest sealed proposal and such highest oral bid, except that if both the highest sealed proposal and the highest oral bid were procured by licensed real estate brokers then the commission shall be divided between them in the manner provided by Section 25532.