how could it be heaving to when it's not heaving to?
When you are moving forward at about 1kt or less, it is Heave-to. When you are stopped in perfect balance under stormy conditions, then you are Hove-to.
Hope that helps. I guess you're supposed to move either very little, or not at all during this procedure. If you move too far forward, I believe the answer is to reduce sail area. That's at least what I've had going on with my boats.