Mark Hennebury
A couple of points:

Supersurfacer blade and back-knife are both hollow ground, they have no "flat" side.
Western plane blades have a flat side, the complete surface requires lapping to remove any wear or you would need to apply a back bevel near the tip or as I have done on my planes is to hollow grind the back slightly with a dremmel type tool.
Japanese handplane blades have a hollow ground back. with only the perimeter needing lapping to remove wear at the tip.
Supersurfacers are hollow ground differently than Japanese hand planes. Lay a supersurfacer blade on a flat surface and you will have only two lines of contact; the cutting edge and the back edge.
When lapping you do not lay the entire blade flat on a stone, you only lap the front part , so that you refresh just a small line a couple of mm wide behind the cutting edge.