After the effective date of suspension, the operation of the commission shall be concluded and the funds remaining held by the commission and not required to defray the expenses of concluding and terminating operations of the commission, shall be returned upon a pro rata basis to all producers from whom assessments were collected in the immediately preceding marketing year. However, if the commission finds that the amounts so returnable are so small as to make impractical the computation and remitting of the prorate refund to these producers, the remaining funds shall be withdrawn from the approved depository and paid to an appropriate program conducted by the University of California or the California State University, another state agency, or a federal agency which deals with the purposes of this chapter. If no such program exists, the funds shall be paid to the State Treasury as unclaimed trust funds.