User blog comment:Atsuko-Regalia/Yumemi Nemu, Tone Rion V4, and Nemu Yumemi/@comment-99.235.121.83-20170111052743/@comment-53539-20170111100919

Its not uncommon for companies to create a new vocal based on a provider and keep alive the older vocal. Lily V3 comes to mind, the package has the older vocal which was updated for those who liked the old V2 vocal. However, they added a newer version which was more accurate to the older provider.

Its often a note that many Vocaloids don't sound like their providers and this can be a little bit of a touch and go subject. Luka V4x's update made the VA happier as Luka sounded more like her... So I'm guessing this is the issue. When you buy a vocal voiced by a famous singer, you kinda want the voice of the singer most often then not. So when it doesn't sound enough like them, it can spoil things.

Tone Rion was also originally part of Vocaloidol, so this might be more of the reason for the seperation. The project is basically dead.