I was going to ask the same question Dennis did, because I encountered the same problem. I thought I'd done it wrong, but realized I'd followed the book's instructions a couple of days ago and just wasn't sure. I didn't want to be rude, because our cabinet would have never been built had Saint not put all this info in one place (thanks man!) but I was concerned - thought I was crazy (probably am, but that's a different story).
One more thing that MAY need to be changed - on page 45 and 46, mounting the speaker shelf, the book says "draw a line that continues the top (horizontal) angle of the cabinet side that leads into the curve." Did that. Don't know that angle was perfect, but am also told "precise angle is not critical." Ok, fine so far.
The problem appears to be on page 46 - "draw a line parallel to this line 3/4" higher. This top line represents the bottom of your speaker shelf." What I discovered was that if I had used the bottom line, not the top line, as the bottom of my speaker shelf, everything would have been recessed 3/4".
At any rate, even though the back pieces are flush, the cabinet is stable, solid, and beautiful. My parents, who have never seen me pick up a power tool, can't get over it and show it off at every opportunity (it's in my Dad's shop).
Once again, despite the errors, it's an awesome book and kudos again Saint for being brave enough to write it...then sit back and watch some of us go "yeah, but this is slightly off"
RTSDaddy2