I believe in both cases--when one diver is OOG or has a computer failure--the conventional wisdom is to end the dive in a controlled but expedient manner. That said, I have seen divers, even divemasters, have the OOG diver remain on their donated reg for a LOT longer than just to end the dive. It seems par for the course that we would also see a diver rely on their buddy's computer a lot longer than just to end the dive.
I think many people in this thread are more concerned about what to do for "repetitive diving" than how to finish out the current dive when a computer malfunctions. There is no repetitive diving concern in an OOG scenario, so it makes sense to me that more people would be fine with relying on air-sharing to finish out a dive when OOG than to rely on computer-sharing when a computer malfunctions.
