(a) Agreed standards. The parties may determine by agreement the standards measuring the fulfillment of the rights of a debtor or obligor and the duties of a secured party under a rule stated in Section 9--602 if the standards are not manifestly unreasonable.
(b) Agreed standards inapplicable to breach of peace. Subsection (a) does not apply to the duty under Section 9--609 to refrain from breaching the peace.