I guess it goes back to the point, what actually defines AT! Because a 're-toning nicely' coin, which many must be out there, or a time-suspended toned coin, which has suddenly been unlocked from its dark place (or slab) to begin a second, possibly third, stage of toning, is that a genuine tone? Really difficult! But, I guess for myself, that, as long as the tone looks natural (ie not accelerated in any way) in its progression, it's all good! Eye appeal is of course king and, to use the OP coin as an example, I'd want to suspend it in exactly the state it's in presently...which also begs the question, if someone had had the same thought in 1920, would it be a lesser coin not to have had its full 100 year whack of oxidation and grime?