Ya. I was shocked too, but Karl invented a new technique to create look-a-like tweed but much lighter, it was introduced in the S/S 05 RTW. The reason for so much fabric is because instead of just a piece of cloth, it is a piece of organdy and threaded through the tiny holes are the tweed threads, and to create the complex Chanel tweeds it would take A LOT of threads. Therefore they get the tweed look without the weight and they get more movement, it doesn't hurt that the price gets jacked up as well.
Kudos to Karl for advancing Chanel, I thought he had done all he could and was just content for mixing up what he's already done.