"Value" is subjective, books like NADA are only a "guide" but it is a "snapshot" in time of what the value was and that snapshot may be out of date with current events.
Today's market, everything costs more, heck be glad your not shopping for a used vehicle right now, the last report on used prices I heard was used autos are selling for well above 40% more than they did only a couple of yrs ago did.. New autos are flying off the dealer lots at MSRP and folks are buying them and flipping for much more than MSRP..
If you want a RV now and most likely the near future your most likely will pay paying much more than you would have a few yrs back.. This isn't going to get better for the short term.
And yes, to me $14.5K for a 5yr old TT does sound high, but then again, I am used to buying much older units for near scrap prices.. If you like it, make a reasonable offer below $14.5K that you feel comfortable with and see if they accept or counter, sometimes folks just throw out a number to see if it sticks.
