Squishy said:
That's a torso bend, not a torso twist?
And how come your line goes from the front of the neck to the sternum's ventral side, and then directly connects from there to the dorsal side of the sacrum by cutting through upper anterior of the waist toward the posterior of the pelvis, completely disregarding the suggested alignment of the waist as indicated by the waist bow?
I'm pretty sure that line does not represent the spine nor the body's vertical axis due its shift along sagittal plane. And that abrupt bend from the chest doesn't even follow the curve of her posture, not to mention the lack of any rotation going on. This does not help me understand your reasoning at all.
Since you apparently have a much more expansive of scientific knowledge of human anatomy why don't you please draw how her spine should look?