Even Game vs. Darkness Grace - Compendium Inconsistancy?

[Illydth]

I'm sorry for the question but it looks like there might be an inconsistancy in the rulings in the compendium?

I'm trying to study for the professor test and I've got to admit this particular ruling bothers me.

Under "Even Game" in the Attacks section the last ruling reads:

Q. If I attack with Luvdisc's "Even Game", what happens if I already have a full bench? Do I get to search anyway and put the extra basics into my hand?
A. No, if your bench is full you cannot even do the search part. And no, any "extras" do not go into your hand either; you can only search for as many Basic Pokémon as you have open slots on your bench. (Nov 30, 2006 PUI Rules Team)

Indicating that since a piece of the attack (put them on your bench) cannot be completed that the entire attack would fail.

Conversely under Darkness Grace (and several other places) we see the following:

Q. If you have no Pokemon in play that can evolve, can you still use Spiritomb's "Darkness Grace" attack to search through your deck?
A. Yes. As long as you can pay the attack cost of an attack, you can use it and do as much of it as you can. (Dec 10, 2009 PUI Rules Team)

Indicating that even though a piece of the attack (the fact you have no pkmn in play to evolve) cannot be met (same as with the Even Game attack above) that you should and can do as much of the attack as possible.

These seem to be in direct conflict with each other: on one hand if the entire attack cannot be completed the ruling is that none of the attack should be allowed, on the other hand if the entire attack cannot be completed the player is allowed to do as much of that attack as possible before hitting the "unable to perform this part" step.

Help? What is the difference? If judging, ruling, or even playing in a situation like this what should I be looking for to make the determination between "don't allow" and "allow even though you cannot complete".

Thanks in advance!

--Illydth

[PokePop]

Note the dates of the rulings.
That was to the best of our knowledge at the time.
As we learned more about how the Japanese game designers want things to work, we update how we rule.
I'll see if we can go back and fix that ruling, but no one plays that card, so it didn't come up.