Ensure that the written acknowledgement and acceptance of the rated order from the subcontractor is received within the statutorily mandated timeframe: within 10 days of receipt for DX rated orders, 15 days for DO rated orders. A not-so-funny flub I've seen on this front is the "stealth backdated subcontract" - where the prime types in the signature date (which just happens to coincide with the POP start date) but the sub didn't get the memo and executed with the actual date of signature ... two months later.