(a) Each person who first handles grapes shall pay to the committee, upon demand, such handler's pro rata share of the expenses which the Secretary finds are reasonable and likely to be incurred by the committee during a fiscal period. The payment of assessments for the maintenance and functioning of the committee may be required under this part throughout the period it is in effect irrespective of whether particular provisions thereof are suspended or become inoperative.

(b) The Secretary shall fix the rate of assessment to be paid by each such person during a fiscal period in an amount designed to secure sufficient funds to cover the expenses which may be incurred during such period and to accumulate and maintain a reserve fund equal to approximately one fiscal period's expenses. At any time during or after a fiscal period, the Secretary may increase the rate of assessment in order to secure sufficient funds to cover any later findings by the Secretary relative to the expenses which may be incurred. Such increase shall be applied to all grapes handled during the applicable fiscal period. In order to provide funds for the administration of the provisions of this part during the first part of a fiscal period before sufficient operating income is available from assessments in the current period's shipments, the committee may accept the payment of assessments in advance, and may also borrow money for such purpose.

(c) Any assessment not paid by a handler within a period of time prescribed by the committee may be subject to an interest or late payment charge, or both. The period of time, rate of interest, and late payment charge shall be recommended by the committee and approved by the Secretary. Subsequent to such approval, all assessments not paid within the prescribed time shall be subject to the interest or late payment charge, or both.