The Regents of the University of California may include or cause to be included in a contract for a construction project for the University of California a provision establishing the time within which the whole or any specified portion of the work contemplated shall be completed. The provision may provide that for each day completion is delayed beyond the specified time, the contractor shall forfeit and pay to the Regents of the University of California a specified sum of money, to be deducted from any payments due or to become due to the contractor. The sum so specified is valid as liquidated damages unless manifestly unreasonable under the circumstances existing at the time the contract was made. A contract for such a project may also provide for the payment of extra compensation to the contractor, as a bonus for completion prior to the specified time. Such provisions, if used, shall be included in the specifications and shall clearly set forth the basis for such payments. Nothing in this section restricts the authority of the Regents of the University of California to include any other provision concerning liquidated damages in any contract for a construction project.