Using what I've read in this thread as a baseline, I've heard similar claims about the IE800 multiple times.
I've also seen a number of people respond to that by saying the treble becomes fuller if one performs a burn in. The most common suggestion seems to be 10-12 hours of higher-than-a-human-can-safely-listen-to volume. As opposed to a more typical burn in process which usually suggests regular listening volumes for 24-48 hours.
Not really sure about those claims, but I'm willing to give it a shot.