A deferral agreement shall:
(1) Be in writing and be signed by the parties;
(2) Incorporate by reference the transaction to which the deferral agreement applies;
(3) State the number of installments or partial installments to be deferred, the amounts thereof, the date or dates originally payable and the date or dates to which payment is being deferred; and
(4) If there is a deferral charge, state the amount to be paid by the buyer for the privilege of deferring the installment or installments.