The Grand Seiko seems to have inner and outer AR coating. If you hold it against a desk lamp e.g. you will see three dimmed reflection of that white light: the first reflection with a bluish tone comes most likely from the inner anti-reflective coating. Then there is a greenish reflection, most likely from the outer AR coating.
I was informed by a fellow watch enthusiast (Paul B., USA) that the AquaTerra does in fact have AR coating, however compared to the Grand Seiko it is not comparable in effectiveness. When I first wrote the article, I said that the AquaTerra did not have AR coating. And when handling the watch and especially when trying to photograph it, it certainly felt like the watch did not have any AR coating. So obviously it has, it is just not nearly as effective as on the Grand Seiko.