ActionScript 3.0 :: Recalculate Point X / Y Value After Matrix Transformation

I am doing a matrix transformation on a Display Object. I got this function from another site, but basically it scales a display object around any point.
ActionScript Code:
public static function scaleAroundExternalPoint(m:Matrix, x:Number, y:Number, multiplier:Number):void{
m.translate(-x, -y);
m.scale(multiplier, multiplier);
m.translate(x, y);
}

But my problem is that I have to do multiple scales in a sequence and after scaling, the points defined in the XML no longer correspond. Let me first say that all the points being scaled around are located in an XML file. They are all relative to the display object's registration point (0,0) when it is normal, i.e. a scale of 1. Also, I have created a class that retains the target object's original Matrix so that the percentage you pass in is relative to the original scale instead of the scale after each call. But basically, with the scaleAroundExternalPoint function by itself, if I have an object that I scaled to twice it's size, the multiplier would be 2. but say I want it back to it's original size. The multiplier would NOT be 1 since that would just leave it at a scale of 2x. It would have to be .5. The important parts of the class are below.

ActionScript Code:
public function ZoomUIComponent(isKeyboardControlled:Boolean = false, disabledAlpha:Number = .25,
max:Number = 2, min:Number = .5, precision:uint = 2,
seconds:Number = 1, step:Number = .1):void{
this.disabledAlpha = disabledAlpha;
this.inControl = InteractiveObject(getChildByName("zoomIn"));
_isKeyboardControlled = isKeyboardControlled;
[Code] .....

It's retaining the original matrix and then calculating based on that EACH TIME. So how would I find the new X and Y values of the original points so that I can scale around them?