(1) WAIVER OF DISPOSITION NOTIFICATION. A debtor or secondary obligor may waive the right to notification of disposition of collateral under s. 409.611 only by an agreement to that effect entered into and authenticated after default.(2) WAIVER OF MANDATORY DISPOSITION. A debtor may waive the right to require disposition of collateral under s. 409.620(5) only by an agreement to that effect entered into and authenticated after default.(3) WAIVER OF REDEMPTION RIGHT. Except in a consumer-goods transaction, a debtor or secondary obligor may waive the right to redeem collateral under s. 409.623 only by an agreement to that effect entered into and authenticated after default.