Each handler designated by the board, pursuant to regulations issued under the plan, to make payment of assessments shall be responsible for payment to the board, as it may direct, of any assessment levied on potatoes; and such handler may collect from any producer or deduct from the proceeds paid to any producer, on whose potatoes such assessment is made, any such assessment required to be paid by such handler. Such handler shall maintain a separate record with respect to each producer for whom potatoes were handled, and such records shall indicate the total quantity of potatoes handled by him including those handled for producers and for himself, shall indicate the total quantity of potatoes handled by him which are included under the terms of a plan as well as those which are exempt under such plan, and shall indicate such other information as may be prescribed by the board. To facilitate the collection and payment of such assessments, the board may designate different handlers or classes of handlers to recognize differences in marketing practices or procedures utilized in any State or area. No more than one such assessment shall be made on any potatoes.