IMO, I think it's surely fixed. I've tried to play a friendly match between my two teams (just call A ad B team). It was 1-0 for A at the 60th minute, so I have put a ST subtituted for the GK of team A. What do you think ? With 20 minute left, team B could not score a goal and was lost 1 more. Remember that team B's quality is better (23.4) than team A (15.6) and both team played with the same formation and tactics (4-5-1V motivation with normal mental). After the match, the subtituted ST'mark was 8 lol.
I hope some of you would try more to have the exact answer.