I guess I've just never heard of anything being called "icewine" (or wine of any kind) that was frozen and concentrated after fermentation. There are a variety of alternative ways to achieve the initial concentration by freezing the fruit or the must, but that always happens pre-fermentation, not post-. That's one reason why icewines typically have lowish alcohol - the sugar content of the must is so high that the yeast can't fully ferment it.

Icewine, though, is traditionally made by pressing frozen grapes to produce a highly concentrated juice, then fermenting that. It's not produced by freezing an already fermented alcoholic liquid.