"Anonymous, why don't you just ask someone else instead of carrying all this on?? -or, it sounds like you like to carry it on, like it's fun.
oh well, I hope you sort out your dilemma."
I don't have any dilemma about this.
I'm quite happy with the answer I received from two of the best dancers in the world.
And I find it a bit more than coincidental that Jonathan's feather step and quickstep videos demonstrate how this detail can add to the quality of movement. I'd actually guess that many people out there are doing it without even knowing that they are, because they've simply moved towards doing what works best.
Provided you plan on using a lot of knee bend in your lowering, it is plainly necessary get the heel down relatively early, before you bend your knee. If you keep the heel up until your feet are closed, you'll miss the chance to descend on a smooth path towards a deeply bent knee.