@Angel - Let's not bring in complications like that. OP has long been established so fans tend to take name changes seriously. And may I ask, is that a fan-made name translation or an official one?
On Gackpo thing, may I bring in the official site of Gakupo on Exit Tunes?
Here, it says "Gackpo" http://gackpo.jp/
So I think the name change is not a name change as it may have been like that from the beginning. We just assumed.
Edit: Oh and here , if you look up the album "EXIT TUNES PRESENTS 煌百花繚乱舞踏会 feat. 神威がくぽ from がくっぽいど", the description says in capitals the word "GACKPO".
I'm not saying EXIT TUNES provides what we call official info but it's the closest thing to official if I might say so.