Bottom-up vs. Top-down scaling

It seems like a lot of scaling chains are either anchored at the bottom and/or the top.

On the one hand, you can put a feat/accolade at the bottom of the chain and see how far everyone scales above that (e.g. Nyriss scaling down to Traya ragdolling 3 Jedi masters). On the other hand, you can put a feat/accolade at the top and see how far down everyone is (e.g. how far someone is from Sidious).

You could make the argument that it's more likely to have disparate outliers at the top between eras than for the average combatant to be massively different, and so we should scale from the bottom, but you could also say that the top ones have clearer differences in feats and accolades, so we should scale from there.

What are your thoughts?