Zoom to visible scale - HTML5 viewer

I'm seeing some unusual behavior when clicking on "Zoom to visible scale" for layers in my HTML5 viewer. My address service is broken down into 5 layers, drawing my address icon at different sizes for 5 different scales. When I click on "Zoom to visible scale", the viewer zooms to a scale that is 1 level smaller than it should be. For example, for the layer associated with a 1 : 1200 scale, it will zoom to a 1 : 2400 scale. Furthermore, it will zoom to some other area of the map - not centered on where I was when I clicked on the zoom to visible scale. Has anyone else experienced a similar issue? Any ideas?

I am using Essentials 3.15, Silverlight 1.10, and HTML5 1.3