Here are my TWO charts. I wanted to ascertain that the chart Sennheiser sent me wasn't a random and arbitrary graph that they manufacture just to satisfy HD800 owners' curiosity. So, I registered my HD800 with both the Sennheiser Asia and Sennheiser USA websites and requested from both a separate certificate.
[From the Sennheiser USA website]
[From the Sennheiser Asia website]