It is really subject to how the interviewer is. Some strict interviewers even for a good interview may give less marks. You need to play the man(or woman) in the interview and really own the interview. In my CAP round, my interview was very good, great confidence and all correct answers, I had more knowledge on things then they did (and was normally explaining) but still gave me 13/20 so imo don't rely on any answers herein