All the grammarians I know say what
Smyth writes: "it denotes a past fixed state resulting from a completed action". They don't refer to a special use in Homer.
Kühner quotes
Iliad, E (5), 65s, where a [face=SPIonic]beblh/kei[/face] "he had (already) hit (his ennemy)" means that the ennemy was already in a sorry state when his opponent "finished" him.