In a cost-plus fixed fee arrangement, what must the engineer keep detailed records of?

In a cost-plus fixed fee arrangement, the engineer is required to keep detailed records of all incurred costs because this contract type allows the engineer to be reimbursed for actual costs incurred plus a fixed fee. Proper documentation of all incurred costs is essential to ensure transparency and accountability in billing. By meticulously tracking expenses, the engineer can provide an accurate and justifiable account of costs to the client, which helps maintain trust and clarity in the contractual relationship. This record-keeping is crucial for financial oversight, enabling both the engineer and the client to understand how funds are being allocated and spent throughout the project.