Symmetry also makes the passages of the weight through the heel obvious: In a continued movement in closed position when one partner rolls their weight forward through the foot, the other partner rolls their weight backwards through their foot as a coordinated, complementary action.
If the man lowered TH out of the chasse, as soon as his weight is in his toe, the lady's weight must be in her heel. If he is going to have the lady's weight initially in her toe, and then lead its progress back to her heel after the free foot passes to begin the next step, then his weight must lower to his heel and move forward as part of how he leads her weight to move back.