The construction manager warrants that the work will be completed at or below the GMP with provisions for change order adjustments for owner-directed work that is outside the agreed-upon GMP work scope and not otherwise covered by the contingency. The GMP shall be based on design documents that are not less developed than 50 percent construction documents for the applicable scope of work. The GMP shall be agreed to as an amendment to the contract between the procurement agency and the construction manager.