The Amiri flight and cabin crews are on call 24/7. Spouse of one of the crew here by herself at the New Years party and her husband just phoned and told her he did not know when he would be home. Flight time limitations for the crews quite a bit more "flexible" as it is considered a private flight.
Tough job with some benefits. Believe most would prefer a schedule.
I'm ok with the 24/7 also. I like the ad-hoc nature of the job; anywhere, anytime. It makes things interesting. Sure, occasionally we have very long days and some gruelling trips but in general, I feel our role is enjoyable. However, it is certainly not for everyone. Horses for courses as always.