Two things:
One, the lady does not extend backwards "to the tip of her toe", but rather she extends backwards with the tip of her toe tracking the floor. This implies the critical detail that the early extension is taken mostly with the lower leg, the upper leg remaining nearly vertical. The difference may seem subtle but it's actually quite important - the note is not to describe reaching of the free leg via division of the upper legs, but to describe the position the foot takes as both body and foot are moving backwards. Actually reaching "to the tip of the toe" is likely to result in an excessively large stride and the bodies falling in between the feet. But even before that, it feels like an obstructed movement to the partner since reaching the foot tends to go hand in hand with insufficient movement of the body over the standing foot during the pre-extension phase of the step - the lady starts out not moving her body enough to match her partner, then tries to catch up by extending her entire free leg back... she manages to move "not enough" and "too much" both in the same step!
#2... The official word on when TH becomes heel vs. when the free foot passes is given as a one-sided inequality - the latest time that the heel can lower is the instant that the foot is passing, but there is no given limit to the earliest time. Many teach substantially earlier - almost as the free foot is only starting to close. If one delays the shift of weight to the heel until the body is already over the standing foot (something likely to happen before the free foot closes), then it will be very hard to actually let the weight arrive in the heel without having to send it backwards against the travel. For this reason, it's my guess that during the T phase of a forward TH step only part of the body weight is actually supported by the foot - the rest is literally in flight, with the full weight arriving only as the heel lowers. After that, the standing leg flexes and the free leg draws in.