According to FAR 16.601(b): "The contract shall specify separate fixed hourly rates that include wages, overhead, general and administrative expenses, and profit for each category of labor." In other words, you don't get paid for G&A separately in any circumstance with a T&M contract. G&A gets "indirectly" paid under the charge for labor. No profit or G&A can be added to Travel either, which is actually considered a type of "Material" for reimbursement purposes. So you don't add G&A expense directly to the offer. It is already included in the proposed labor rates.