The prescription at FAR 17.208(g) for exercising FAR clause 52.217-9 uses the phrase "any or all" related to subparagraphs (1) - ...preliminary written notice of its intent to extend the contract; (2) -...the contract includes an extension of the option; and (3) - A specified limitation on the total duration of the contract. Has anyone ever used just one or two of the subparagraphs? If so, can you briefly explain why?