Well, this is based on my personal experience with 663. This may not be actually correct, but I will recount what happened.
I connected a Pioneer 610 and a Yamaha 663 to a Samsung Series 5 FullHD TV (46 inches). I used both Avia 1 and Avia 2 DVDs to set the systems up. Avai has a screen set up that includes colour, brightness, tint, etc. In contrast, the screen is divided into two parts. The right half is white, while the left is black. In the left side, Avia has two bars oscillating on the screen. To set the correct level, you adjust the TV contrast till the left bar disappears, and the right bar is just visible.
I first I connected the TV through the AVR. I tried Avia 2 and I could not see the bars at all. I tired Avai 1. Again I could not see the bars. Getting frustrated, I was wondering what to do. Then I decided to connect the TV direct to the Pioneer 610. On both the DVDs, the bars were clearly visible. I then used this connection to set the TV up.
When I then connected the TV through the AVR, the images were perfect.
Cheers