In a sense... "zone Anakin" is Anakin without any inner conflict, fighting with a focused, controlled anger. It does make a difference, but not as much as people believe.
The problem is that many take Stover's flowery first person descriptions at face value. Dooku "summons power from all over the universe" or feels he "becomes the axis of the universe", Anakin has a furnace heart, Sidious is black hole and an event horizon, each of Anakin's blows aged him 10 years etc.
People need to separate a character's inner thoughts and feelings from reality.
Zone Anakin is simply Anakin operating at his peak, like an athlete giving it his best during the Olympics. His power level doesn't just magically shoot through the roof.
Even if it did, it's very circumstantial. A few things had to happen for Zone Anakin to exist.
If Obi-Wan wasn't there, Dooku would have killed him. If Dooku hadn't taunted him, his anger wouldn't have surged, if Sidious hadn't "given him permission" then Anakin would have still been emotionally conflicted and probably lost.