[5] All three of these clauses give the government the right, at any time and without notice to the sureties, to make changes in the work within the general scope of the contract.
The clause for fixed-price contracts specifies that changes may be made to the specifications (including drawings and designs), the method or manner of performance, government-furnished facilities, equipment, materials, services, or site, or acceleration of the work.
If they are unable to agree, the contractor is entitled to an equitable adjustment in accordance with the cost principles contained in Part 31 of the FAR.
The clause provides for such an adjustment to be made in the estimated cost, delivery or completion schedule, and the amount of any fixed fee.
[12] There are a number of basic rules regarding the Changes clause that have been developed by the courts and boards of contract appeals over the years.
One of the fundamental tenets is that a contractor cannot claim an equitable adjustment where it incurs additional costs or performance delays voluntarily, rather than as a result of government action.
Where, however, a contractor and the government are both responsible, through their unreasonable acts, for failure to discover a differing site condition, the costs of the delay have been ordered shared.