The time difference between when the sun goes down will vary depending on how close you are to the center of your time zone.
If you are exactly center in your time zone, you will have the sun set @ the same time as someone else who is exactly center in there time zone. (-1 second when entering winter, -0/+0 when in winter/summer +1 second when entering summer)
as a time zone is 60minutes, if someone is on the far west side of there time zone, and you are on the far east...you could have close to 119 minutes difference in the time the sun is "setting" for them. (assuming the time zones in question are side by side)