Why didn't Durkon Plane Shift to Celestia to talk to Roy?

[Saint-Just]

SO now that begs the question, why didn't Durkon just cast Sending to talk to Roy? That's easier than Plane Shift and has a 95% chance of success when talking to someone on another plane. However, I don't think the rules of D&D were meant to include "talking to a dead person who is living in their afterlife plane" as something the Sending spell could reasonably do, and regardless, I don't think it would make logical sense to work that way in this universe either.

There was a discussion on 3.x forum a while ago which concluded it is 100% RAW-legal to contact almost anybody (e.g. Deities) with sending but about nobody has ever heard about doing it in real play - not only from the concern about balance, but also because it seems so contrary to the intent to have all those Contact Other Plane etc. if Sending worked just as well.