Hearth Pad? Pic Included

So I decided to redo my existing hearth in anticipation of my new Quad Fire 4300. On the existing wooden hearth pad, I am going to put down 2 layers of Durock which should meet Quad's vague hearth protection (r value) requirement. The problem that I have is the pad will only extend 6 inches in front of the stove....not enough. I am going to tear out several rows of hardwood flooring to meet the 16 inch requirement. Because of a nearby doorway, i cannot raise the floor in front of the "pad" above the existing grade. As such, I will only be able to put down Hardi Backer Board topped with mortar and 1 inch of stone. My stove dealer told me that r value is only an issue directly under the stove and only ember protection is needed out front. Does anyone have any experiences with this? Thanks

Any thoughts on whether or not the stove dealers comment about only needing ember protection out in front of the stove carries any water?

I have also heard that the R value requirement does not play a role beyond the hearth pad when the hearth is raised above the floor grade; however, I have not seen any documentation to support this.