I'm skeptical that one can tell which novels were plotted out beforehand just by sensing how neatly they're integrated. Isn't it possible (indeed likely) that someone who wrote in a piecemeal jumpy fashion also pays careful attention to consistency?

Wasn't that in fact the author's point with his "negative twenty questions" analogy, that novelists who write in that piecemeal jumpy way nevertheless achieve coherence through careful attention to their constraints?