(from a recent conversation on Facebook about the twist stance)
All stances are "mobile" however some have more momentary stationary applications than others. The "Twisted Neutral Bow" as we used to call it, is a more mobile stance than others in that its design is more transitional than most and its primary purposes are built around its mobility. "How" you get into a stance also has a significant impact on its applications. This is in significant contrast to a stance like a "forward" or "neutral bow" that although is "mobile" their significant purpose is "stability" not mobility at the moment of application. Also, many forget the application of the twist as a mobile platform on an incline or uneven surface to maintain upper platform stability while the lower platform can sustain itself at varying heights.