"I can see the point. But it must seem a bit strange the the lady is up and the man obviously down on the last step."
No, the lady is not up, see the rise and fall column. What the notation of "T" means is that the lady's weight is still in the toe of the foot - it has not moved to the heel, because the timing with which it does so is dependent on the full action of the next step as appropriate to the next figure. If it's a natural turn, her footwork would become TH, No foot rise, but if it's another fishtail she will spring up from the toe of the foot, and if it's a connector to a reverse figure her weight will stay in the toe until after the left foot passes and only reach the heel after the official end of the step, hence the position of heel is never actually given.
"Len Scriviner wrote that he has not met any professional teacher who doesn't think that to keep the ladies head to her left is more comforable dancewise than to be in promenade when dancing the Whisk."
Yes, the classic masters often taught this way for the first few months. That doesn't mean they stay that way forever, but it does illustrate how there is no requirement to turn the head over at all.