I'm not sure why "tube" names have been so popular lately. I definitely think of it as a fad. You should cash in on it if you can. Regarding the official appraisal - they will tell you $x,xxx for any name you pay them to appraise. Not many people will look at a sedo appraisal and say, yes now I am certainly going to pay $x,xxx for it.
Honestly, the amount you spent on the appraisal would have been my max bid on this domain if it were at auction (IF I even decided the name was one I would be interested in). I think with the "tube" hype it is flippable for a profit unless you have already paid alot for it. Sorry I haven't yet looked at the site and cannot guess the value it adds or how much traffic it receives. Good luck!