how can I apply updates to ColorGradientFilter and the DropShadowFilter?

[stylustrader]

After creating an instance of the outline filter, i am able to set new values into the thickness option dynamically using the following syntax:

this._outlineFilter = new OutlineFilter(2, 0x000000);

...
//then later on, 
          if(barWidth <= maxBarWidth){
              this._outlineFilter._thickness = lineWidth/2;

              //change the colorgradient distance as well
              this._colorGradientFilter._stops[1].offset = 0.5

          }else {
              this._outlineFilter._thickness = maxBarWidth/2;


              this._colorGradientFilter._stops[1].offset = 0.2
          }

I can visually see the Outline thickness changing dynamically, but when I apply similar approach to change options for colorGradientFilter or dropShadowFilter, the values do end up change, but it doesn't reflect on the actual rendering of the object. It stays the same, using the options prescribed when initializing the new Class.

Do I have the incorrect syntax here? Is it even possible to change some of the option values for these filters?