A T&M contract must have a not-to-exceed (NTE) clause or the cost can spin out of control. 1 is incorrect because while a signature is needed on most contracts, a T&M demands an NTE clause... or else. 2 is incorrect because not all T&M contracts require an end date 4 is incorrect because changes can spur new contracts, be covered by the existing T&M contract, or have addendums.