Yes it's a bit more difficult to get 80PLUS Gold 230V EU when you compared to 80PLUS Gold, but that's actually a good thing. If 80PLUS Gold 230V EU would need 87%, 90% and 87% efficient then no one would use 80PLUS Gold anymore, which means that it's more easier to get a 80PLUS Gold label, even if that means it's a 80PLUS Gold 230V EU label. 99% of the people wouldn't know the difference. But that means that the efficiency would go down because manufactures are gonna choose 80PLUS Gold 230V EU over 80PLUS Gold.

That of course can't happen, so they have chosen a higher requirement. One that is more comparable with the efficiency boost that you will get on 230V.