Why are they different? The P43, P61, and P68 are basically the same stove except for size. I am confused why the P43 and P61 need a hearth pad with minimum r .45 protection, but the P68 manual says that a 20 gauge piece of sheet metal would be fine. The P68 is a bigger (hotter???) stove so shouldn't that stove naturally need more thermal hearth protection than it's smaller brother and sister, the P61 and P43? I have been researching hearth pads and the Harman P-series recently and discovered this difference between these similar models. Can someone enlighten me? Maybe I am just too stupid to figure it all out.