The process is more objective than subjective for the FAR 52.243- series of Changes clauses (for non-commercial items), as the clause text is fairly clear about what constitutes an in-scope change subject to the Changes clauses. As for modifications which may require Justification and Approval iaw FAR Part 6, the determination of whether a modification is within the scope of an existing contract can be somewhat subjective. Because contracting officers have basic responsibility for modifying contracts and for promoting full and open competition, authority for determining in- and out- of scope rests with them and use of sound business judgment.