His trip for ‘critically-important foregin business’ was really a family vacation. Since the girls have to be back in school and can’t go, the real purpose for the trip is effectively gone. Once he delayed to a Sunday departure the whole reason for the trip was compromised(that’s why Australia got shortened to a refueling stop). So cancelling it at this point is an easy decision from him. You just won’t hear Gibbs say (well he can’t take the planned family vacation now).
Forgot to add that the girls will be out of school in June.
So no suprise that the rescheduled trip is not happening in April or May.