If this is five discs and 2 of the 5 are special features, then shouldn't Part II be double sided. I heard someone say it is only one disc. Part II has been released on 2 discs before b/c it is so long. Wouldn't putting it on one single sided disc ruin the quality?
The original box set used single-layer DVDs, hence the need for two discs to fit Part II. This new set uses dual-layer DVDs, so the second movie easily fits on one disc. And if you get the bluray set, they even fit all the bonus features on 1 disc.