I'm going with the FAA definition and the FAA has consistently maintained that reserve time is not duty, it just is not rest though I'm not 100% sure about 117, which doesn't apply to us anyway. Also, I glanced at the contract but did not find anything there but I may have missed it.
See McCormick interpretation, 1996.
https://www.faa.gov/about/office_org...rpretation.pdf
Fortenberry (1991)
https://www.faa.gov/about/office_org...rpretation.pdf