After 20 years of playing i found out
To become a superstar you need 10 charisma, 9 creativity, 8 body and i saw how using the movie set had a higher chance of my sim succeeding the gig then the runway. I failed the runway a lot, succeeded movies almost everytime. So i tried to bring my fitness to 10... and now im succeeding almost every time at the runway too???
I did not know improving your skill after the skillpoints needed gave you a higher chance at succeeding?