Each handler required to pay assessments under a plan, as provided for under section 4906(f) of this title, shall be responsible for payment to the Board, as it may direct, of the assessments. A handler also shall collect from any producer, or shall deduct from the proceeds paid to any producer, on whose watermelons a producer assessment is made, the assessments required to be paid by the producer. The handler shall remit producer assessments to the Board as the Board directs. Such handler shall maintain a separate record with respect to each producer for whom watermelons were handled. Such records shall indicate the total quantity of watermelons handled by the handler, including those handled for producers and for the handler, the total quantity of watermelons handled by the handler that are included under the terms of the plan, as well as those that are exempt under the plan, and such other information as may be prescribed by the Board. To facilitate the collection and payment of assessments, the Board may designate different handlers or classes of handlers to recognize differences in marketing practices or procedures used in any State or area. The handler shall be assessed an equal amount as the producer. No more than one assessment on a producer nor more than one assessment on a handler shall be made on any watermelons.