If it works, it works and if it doesn't, it doesn't. Just because it doesn't get there the way you'd like it to doesn't make it a bad thing. I also wonder how they figured out the disposal emissions for the 400 lbs of the Volts battery. To my knowledge, there aren't any facilites that can do it, and there won't really be a need for them for quite some time. Its one thing to analyze the recycling cost of steel, aluminum, or plastic. Those are all mature processes. But Li-ion recycling is in its infancy at best right now. Anyone who predicts what it will be in 10 years is essentially guessing.
I wonder, do they include the half a million gallons of bunker diesel that ships burn when they take a load of Priuses from Japan to America? Or do they ignore that out of convenience?