Full Idea
The reason the two predicates 'before' and 'after' are needed is not to express different relations, but to indicate its order. Since there can be difference of order without difference of relation, the nature of relations is not the source of order.
Gist of Idea
'Before' and 'after' are not two relations, but one relation with two orders
Source
Keith Hossack (Knowledge and the Philosophy of Number [2020], 10.3)
Book Reference
Hossack, Keith: 'Knowledge and the Philosophy of Number' [Routledge 2021], p.157
A Reaction
This point is to refute Russell's 1903 claim that order arises from the nature of relations. Hossack claims that it is ordered series which are basic. I'm inclined to agree with him.