I accept the proof, but you may get more people on your side if you found and added just one or 2 more links selling for 1.66

I personally buy these from quicksellers for 1 ref (its my fourth most common item), and trying to re-sell them for 2 ref is more difficult every time. Upvoting this.

Its pretty easy to buy those for 1.66 refined, but your evidence just shows only 1 at 1.66 so while I think 1.66 - 2 is an accurate range, your evidence for it is lacking.