Extension or deferment.

(1) The holder of a home improvement contract, upon agreement in writing with the owner, may extend the scheduled due date, or defer the scheduled payment, of all or of any part of any installment. All terms of the agreement shall be in writing.

(2) The holder may charge and contract for the payment of an extension or deferral charge by the owner and collect and receive the same, but such charge may not exceed an amount equal to 1.5 percent per month simple interest on the amount of the installment or installments or part thereof extended or deferred during the period of extension or deferral. A minimum charge of $1 for the period of extension or deferral may be made in any case where the extension or deferral charge, when computed, amounts to less than $1.

(3) Such agreement may also provide for the payment by the owner of the additional cost to the holder of the contract of premiums for continuing in force until the end of such period of extension or deferral any insurance coverages provided for in the contract.