[EDIT]: Headphone tone and response also changes over time - what sounds ideal at 0 hours will sound very different after 100 hours of break-in and use.
Would help if there was a note about this on the site, and recommendations for basic steps you can take to correct for these.
I'm spoiled - headphone.com is based out of my hometown, so I can listen to any headphones I want on their expensive equipment and find what really works the best.