I'm not sure where people are getting the impression that an athletic stance for skiing means a heel raised. I can't think of anyone in the ski business that would advocate that.
When I first started racing some 25 years ago, race coaches emphasized BOF as a focal point for where your COM should be at turn initiation, but with the realization that your COM will move slightly aft to heels at turn end. This is still in alignment, and not at odds with the centered stance chorus. You can't stay on the BOF all the time, neither can you stay perfectly centered--your COM is suppose to move for and aft, no matter what type of skiing we're talking about.
LeMaster writes in Ultimate Skiing: Chapter on Alignment and Stance: "... A football linebacker defending against an oncoming opponent provides a good model for a skier's neutral, homebased stance. … The stance is flexed at all the major joints. Hands are at the same height, about halfway between hips and shoulders. The athlete's balance is on the balls of his feet. With a couple of tweaks--the stance is generally narrower and the balance maybe a hair farther back--this is the basic neutral stance of an athletic skier,"
...
"We often talk about having your balance over your center of gravity, "over your feet." Sounds simple enough, doesn't it? But it's not. At the heart of the issue is what "over" means. It doesn't mean that your center of gravity and feet must be aligned with respect to gravity. It means they must be aligned with respect to the balance axis, as defined in chapter 1. Recall that the balance axis goes through your center of gravity and is perpendicular to the bottom of your skis, and is seldom aligned with gravity [ see figure 1.8 some picture of Bob Barnes skiing]. So when a coach says your balance is over your feet, that means the balance axis falls somewhere between the balls of your feet and the back of your arch when viewed in the sagittal plane. ... "
underline emphasis is mine.