The stock was still only a trillion. No way would the planet be able to provide less energy. At any rate this doesn't necessarily correlate to gods since the grail was full. Grail being unable to summon gods assumed an empty grail during a war.
Fair enough. But what makes you think they draw mana only from the surface?Also if the planet runs on mana. And TAs are extensions of the planet.
Then it would make sense that they get mana from the planet when they request for backup.
Instead of protein powder, glucose packs or Weight Gain 4000.