So a provision was made (exercise of Cmdrs discretion) to allow them to get
home.
Fundamentally disagree with you there
Atom, discretion was not introduced to allow a fit crew to exceed normal hours and get home, I didn't say that couldn't happen, I know it does, have used discretion myself, but the purpose is not to get the crew home, it is to complete the schedule or, at least, get the aircraft and crew into a better operational situation, (not commercial).