From OP:
"Sunlight fades gradually and at dusk chickens prepare to settle into their favorite roosting spots before darkness falls. Chickens have poor night vision and cannot find their roosts in the dark. Adding supplemental light at the end of the day, allows no transition time for them to get positioned for sleeping. This can cause confusion, stress and possible panic leading to injuries. It is better to light the coop in the morning as they will not object to instant sunrise."
Good point. My observation indicates that the chickens start to roost as the sun is setting. If light is on, they would sit on the roost wondering why the sunset is taking so long. I read that the point of lighting is so chickens continue to feed and lay. If just sitting, it is not meeting the objective. Pre-dawn lighting gets them off the roost and feed.
I have been using pre-dawn lights because that is what the pros do. There are hobbyists, not concern with egg production, claim that letting chickens rest over winter is better.
Well, this year, since I have brand new layers (started in August), I plan go with out lighting to see if and when production starts to slow. So far, the day light is about 11 hours, and has not affected the production rate.