When it comes to disciplining an 11-year-old versus a 6-year-old, there are obvious differences. My daughter will often complain that I am harder on her than her brother, and she is absolutely correct on that.
I expect her to set an example for him, act like the older child, and be able to listen. While my son may get a six-minute time-out, she will get her electronics taken away for the rest of the day for misbehaving. A simple time-out wouldn't be effective for her at this age. My son wouldn't care if he didn't have electronics for the day, while my daughter thinks it is the end of the world.