Nice! That sounds like an impressive optimization, but I assume debugging and improving HLSL is quite a bit more annoying than doing the same in C++.
While more speed is better of course, I also want to say that don’t actually care much about how long it takes to generate an LOD, I only care about how good it looks. The LOD generation is only done once for every mesh in the editor, but the rendering of it is done all the time for the player, so even if I have to wait 1 hour once to generate a perfect imposter, I’d happily do that if the quality is great.