Most US Airlines have several things in common different from non-US Airlines. Are these FAA regulations?

For example, most non-US airlines turnoff the seatbelt sign 5-10 minutes after takeoff while US airlines wait until "cruising altitude" which is around 15-20 minutes after takeoff. Another one is that mobile phones in US airlines may be used while the door is open before takeoff and immediately after landing even if the aircraft is still moving towards the gate.