Sorry mate, but, respectfully, I completely disagree with you. Whatever algorithms they have for the match engine clearly favour the A.I. It is easily proved - make a copy of a save and play a season (or series of matches) as yourself and in the other one let an A.I. manager take control of the same team. The difference in results is clear in even a small representative sample. I use detailed tactics, and even bad/complete absence of tactics cannot account for the discrepancy. Just the vast number of late goals the A.I. teams score against the user (even though my players' conditions are always ~10% better per player than the oppo) while the user hardly ever gets any blatantly shows the bias.
Its not all down to fitness though. Concentration and determination of the squad and also composure on most parts is needed to prevent your team from switching off. The events of matches can also impact late on with teams having momentum such as coming from behind. You also need to react to the change in tactics from the opposition or a substitution. I, myself have scored loads of late goals and conceded many too, it's frustrating but look at real life. IMO there isn't enough late goals in the game compared to real life but thats just me. In FM there are so many factors that can influence a single event and if you look closely enough they do IRL as well such as form, mental state, personality, morale, tactics, weather, crowd, pressure etc.