Section 4.143 - Effects of changes or extensions of contracts, generally(a) Sometimes an existing service contract is modified, amended, or extended in such a manner that the changed contract is considered to be a new contract for purposes of the application of the Act's provisions. The general rule with respect to such contracts is that, whenever changes affecting the labor requirements are made in the terms of the contract, the provisions of the Act and the regulations thereunder will apply to the changed contract in the same manner and to the same extent as they would to a wholly new contract. However, contract modifications or amendments (other than contract extensions) that are unrelated to the labor requirements of a contract will not be deemed to create a new contract for purposes of the Act. In addition, only significant changes related to labor requirements will be considered as creating new contracts. This limitation on the application of the Act has been found to be in accordance with the provisions of section 4(b) of the Act.(b) Also, whenever the term of an existing contract is extended, pursuant to an option clause or otherwise, so that the contractor furnishes services over an extended period of time, rather than being granted extra time to fulfill his original commitment, the contract extension is considered to be a new contract for purposes of the application of the Act's provisions. All such "new" contracts as discussed above require the insertion of a new or revised wage determination in the contract as provided in § 4.5 .