I wanted to revisit the definition of "appropriate consideration" under FAR 1.108(d)(3) and commercial items contracts that have 52.212-4 in it. The Changes Clause "(c)" there requires that no changes to the terms or conditions of the contract can occur ONLY with a mutual agreement of the parties. So here are my questions: 1. Are these independent authorities to modify the contract? 2. If so, does FAR 1.108(d) provide a unilateral right by the Contracting Officer to modify the contract? 3. If no, can the Contractor refuse to negotiate "appropriate consideration" and prevent a mutual agreement under 52.212-4(c)? 4. Since "appropriate consideration" is effectively a right to an REA, can the Contracting Officer determine that the appropriate consideration is $0.00 if the Contractor cannot actually establish any additional costs to imposing the new clauses under FAR 1.108(d)? 5. What other remedies might the Government have short of a negotiated resolution under the commercial changes clause, other than the Disputes Clause?