No, it's not a "fixed" rate. The pulls and rolls are rigged.
I suggest people go watch Aristeaus videos on Youtube, about Oasis Games before they keep spending money onto this game.
To avoid the 3hrs watch (Discussed what's going on with the mods, the devs, the way events work, the way Oasis threats the community) you can watch that : https://www.youtube.com/watch?v=Z7VZOKi7jPk
They don't give a *** about the community, they just perceive people as money cows.
The game is well made in its core, but because ****** people are allowed to manage it, the servers keep losing players, and the game is slowly dying.