(a) If a change in plans or specifications is necessary after the performance of a contract is begun or if it is necessary to decrease or increase the quantity of work to be performed or of materials, equipment, or supplies to be furnished, the district may approve change orders making the changes.
(b) The total contract price may not be increased because of the changes unless additional money for increased costs is approved for that purpose from available money or is provided for by the authorization of the issuance of time warrants.

(c) The district may grant general authority to an administrative official to approve the change orders.
(d) A contract with an original contract price of $1 million or more may not be increased under this section by more than 25 percent. If a change order for a contract with an original contract price of less than $1 million increases the contract amount to $1 million or more, the total of the subsequent change orders may not increase the revised contract amount by more than 25 percent of the original contract price.