You pulled up a year old post to "confirm" something with false information that was "verified" in a poor manner? Kudos to you, man.
Yes because testing something on EP and VT mobs in Boyahda as well as EP and DC in Abyssea and EP in Dynamis over the course of a week and getting an average rate of increase of shadow gorget/belt over that of soil gorget/belt is false information being verified in a poor mannor.
Also had friends test various elemental gorget/belts on Tachi: Shoha, another on Stardiver, and another on Requiescat.
All tests showed a difference of damage of ~5%.
We don't simply take the forum's word as gospel when it comes to gear, we test the piss out of it, as should everyone. I'm showing what it did for us, go and do for you and see if you can find a difference. If you already have, then great.