Franklin,
That's weird I don't know what your problem. Could you do the following test to verify if the problem is caused by MapSuite or not?
Don't use xml file, just write code like our HowDoI samples, create 16 ShapeFileFeatureLayer and set the specific styles and apply to zoom level 20, add all layers to static overlay, and then add static overlay to wpfMap, set MapUnit, CurrentExtent, call Refresh(), such as following code. If it works that means it's not the MapSuite's issue, If it still has problem, please provide the code and we can figure out how to fix it.
LayerOverlay staticOverlay = new LayerOverlay();
ShapeFileFeatureLayer ShapeFileFeatureLayer1 = new ShapeFileFeatureLayer(path1);
ShapeFileFeatureLayer1.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = yourAreaStyle1;
ShapeFileFeatureLayer1.ZoomLevelSet.ZoomLevel01.DefaultLineStyle = yourLineStyle1;
ShapeFileFeatureLayer1.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = yourPointStyle1;
ShapeFileFeatureLayer1.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
ShapeFileFeatureLayer1.DrawingMarginPercentage = 100;
ShapeFileFeatureLayer ShapeFileFeatureLayer1label = new ShapeFileFeatureLayer(path1);
ShapeFileFeatureLayer1label.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = yourTextStyle1;
ShapeFileFeatureLayer1label.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
ShapeFileFeatureLayer1label.DrawingMarginPercentage = 100;
staticOverlay.Layers.Add(layerName1, ShapeFileFeatureLayer1);
staticOverlay.Layers.Add(labelName1, ShapeFileFeatureLayer1label);
ShapeFileFeatureLayer ShapeFileFeatureLayer2 = new ShapeFileFeatureLayer(path2);
ShapeFileFeatureLayer2.ZoomLevelSet.ZoomLevel01.DefaultAreaStyle = yourAreaStyle2;
ShapeFileFeatureLayer2.ZoomLevelSet.ZoomLevel01.DefaultLineStyle = yourLineStyle2;
ShapeFileFeatureLayer2.ZoomLevelSet.ZoomLevel01.DefaultPointStyle = yourPointStyle2;
ShapeFileFeatureLayer2.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
ShapeFileFeatureLayer2.DrawingMarginPercentage = 100;
ShapeFileFeatureLayer ShapeFileFeatureLayer2label = new ShapeFileFeatureLayer(path2);
ShapeFileFeatureLayer2label.ZoomLevelSet.ZoomLevel01.DefaultTextStyle = yourTextStyle2;
ShapeFileFeatureLayer2label.ZoomLevelSet.ZoomLevel01.ApplyUntilZoomLevel = ApplyUntilZoomLevel.Level20;
ShapeFileFeatureLayer2label.DrawingMarginPercentage = 100;
staticOverlay.Layers.Add(layerName2, ShapeFileFeatureLayer2);
staticOverlay.Layers.Add(labelName2, ShapeFileFeatureLayer1label);
// do the same way for other shape files
...
wpfMap1.Overlays.Add(staticOverlay);
wpfMap1.MapUnit = GeographyUnit.DecimalDegree;
wpfMap1.CurrentExtent = new RectangleShape(-180, 90, 180, -90);
wpfMap1.Refresh();
Thanks,
James