On Offerings To The Dead

I just came across the Janussonin Sutta on offerings to the dead.

In essence, if you dedicate an offering (or I assume any kind of merit) to a deceased relative, they can only benefit from it if they are in the realm of hungry ghosts. If they aren't there, another of your relatives (the definition of relative in the Vinaya is all those descended from one's great-great-great-great-great-great-great-grandparents) will benefit from it. And in any case the donor will always benefit from his action.