You do understand that RNG is RANDOM. If you asked everyone farming their Atma, you would get an average amount of time it took. Some people might get 1 an hour, some people might get 1 every 24 hours. Your FC members got 2 back to back, you did not. I got 2 in under 30 minutes, an FC member of mine took 10 hours to get 2. It is completely random. There is no way to figure it out. It is the same as to why some people get gear every run of Coil while others have to wait 2 months just to get 1 piece. Random.