I'm converting our contracts to cost plus a fixed rate. When I send my employees to a job I want to invoice for our billable rate for that employee. I fear a difficult customer may say our billable rate is not the cost rate of my employee. Should I add a line to the contract stating: Customer will pay incurred builders costs for sub contractors and materials, and builders employees will be invoiced at a rate of "X" per hour. Should I specify different rates for different labor rates (employee staff).