Originally Posted by
G-BOAC
These are standard miles rules/terminology and I have never questioned this fact or thought about it the way you are saying. In these cases I believe departure means 'commencement of the trip' and that's the way I've always understsood it.
And I'm coming at this after a decade of the cousins at AA who only offer one-way upgrades, and where you certainly can re-credit one-way for the appropriate fee.