Whenever I play Talon I score A+...

No matter how well or decent I score, I can't get S. I just got out a game where I went 13/2/2 and scored A+ while my ally scores 8/3/3 and gets S-. I can't remember when exactly but I had a game with as well where I got fed and scored pretty decent but also got A+ instead of S.

Anyone else is having this or a similar ''issue'' like this? Why can't I score S with and my teammate can? Am I missing something in here? O.o