"On any given day...." I'm sure you've heard that line before so it goes without saying that domains are commodities they're worth whatever the market is willing to pay on any given day. That quote you received was from someone who thinks one value and then you have a value here. Somewhere between the two extremes should be a middle ground for you.
You have nothing to lose by offering it at auction if only to see what the market thinks in real world terms.