Opinions please .But only after looking .We do not need a belief we need facts. And if it is a belief where did it come from.
There seems to be an on going argument about whether the shoulders stay over the hips or whether we have a spine that is sometimes twisted. In other words not as the book has said.
My observations is that in particular the right side stays. It along with the right arm is set as it would be if it were set in plaster of paris. CBM or CBMP can be applied without taking that right shoulder away from its position over the hip.
I will be the first to admitt that a plump person does find it hard using CBM or CBMP. They must get on as best as they can. I might point out there has never been a plump person who has ever won a major title and there never will. That's the way it is in this cruel world of dancing. To be at the top takes a certain type of build even down to the feet which in modern must be straight and not turned out. Has anybody else noticed that all the finalist in a major comp look very much the same in build give or take an inch.

"or whether we have a spine that is sometimes twisted. In other words not as the book has said."

The book does not say that the spine should not be twisted. It mentions that swing is comparatively more important, but it does not by any means prhobit twisting. And since many of those who train world champions recommend things that involve rotating body parts to different angles around the spine, I would recommend not rejecting the idea out of hand.

"My observations is that in particular the right side stays. It along with the right arm is set as it would be if it were set in plaster of paris. CBM or CBMP can be applied without taking that right shoulder away from its position over the hip."

It's not really the right shoulder that moves away from the hip, it is the right hip that moves away from the shoulder.

Also, I think you will find at a higher level that the arms are not really fixed even to the shoulders - there is some flexibility there. But before you can do that, you have to learn to reliably keep your arms with your shoulders to establish basic coordination - only after a few years dancing that way can you start judiciously letting them move independently.

"Has anybody else noticed that all the finalist in a major comp look very much the same in build give or take an inch."

Actually, no. Look at John Wood vs Marcus Hilton. Both are athletes of course, but built differently and dance and related to their partners differently in a way that quite suits their build.