The article isn't implying that you can train yourself to pedal heels down, and therefore lower your saddle. What is stated is that a "heel driver" has a saddle height 3-4cm lower than a "toe pointer" generally speaking, because of the angle of their foot at the back of the pedal stroke.
I don't really concentrate on the location of my heels while pedaling. For me, so long as the knees don't hurt, the saddle is at the right height.
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