No stipulation or agreement between the Parties or their Authorized Representatives, with regard to any matter involved in any Proceeding governed by this chapter, shall be enforceable unless it is reduced to writing and signed by the Parties or their Authorized Representatives or unless it is dictated into the record by them during the course of a hearing or oral deposition, or incorporated into an Order bearing their written approval as to form and substance. This section does not limit a Party's ability to waive, modify, or stipulate any right or privilege afforded by this chapter, unless precluded by law.