(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) of this section does not apply to the duty under section 9-609 to refrain from breaching the peace.