Contractor contracted to install a runway lighting system requiring a double circuit underground conduit. At the direction of the government's "technical personnel," the contractor changed the system to a single circuit that required the digging of several additional trenches along the taxiway. After about a month of digging, the government directed the contractor to abandon the single conduit system. Contractor claimed the added costs of digging the several trenches and the government defends claiming that its "technical personnel" had no authority to direct the change. Decide this issue.