here is gaming mechanism that unlocks encore, premium encore stages based on your skill points but from what I observed
On the statistical observation....
GF players with 800 Skill points should be able to get encore stage ext consitently
GF players with 900 skill points should be able to get premium encore stage
While on DM
DM players with 1200 can get encore stage consistently
DM players with 1400 can get premium encore stage consistently
What you think of my observation
When I say consistent I mean being able to get it every single time the song is played
.... i think so | 
