@ Ziggy..
I do feel that it's very important to make sure that before you turn the lights off, to make sure your grey is perched comfortably on a stable, familiar perch and has her bearing. It is my opinion that the best roosting perch is a nice cotton one installed high up like in Emma's cage. YOu can buy some Comfy brand perches or some custom cotton perches from Mother pluckin bird toys. 1 inch to 1/4 inch is ideal I'd say but not more than 1 and 1/2
Try to imagine how you'd feel if you were swinging around upside down and suddenly found the power had gone out and you were stuck in the dark? Some parrot owner like install a small night light too so their parrots aren't completely in the dark. Personally, I turn off the lights completely but leave and turn on the bathroom light on for about 5 minutes. It is located in the hallway so a bit of light still shines through. This allows my parrots to prepare themselves for full lights out very shortly and get themselves settled.
With that said, this doesn't mean that they have to be in the mood to go to bed.
Don't forget that our parrots are creatures of prey. In the dark they feel quite vulnerable. Doing the above will help minimize feelings of stress or disorientation for your parrot and it is called thoughtfullness on your part. As you can probably tell, Emma comes across as well adjusted. Well, she is, and I would believe that alot of that has alot to do with how we care for her and always have.