Pitcher Fatigue Ratings

So I have read the included documentation on pitcher fatigue ratings and I don't feel like I have enough information here in terms of making the settings for "Don't Relieve B4". First of all, what is the pitch count rating for a pitcher? I'm not sure if that should have been amended if the cards do not indicate what that is for an individual pitcher. My understanding has always been an S(5) can pitch 5 full innings before getting fatigue. And I understand this was added to make the game more realistic. But what is the difference between F(9) and F(8), and F(8) and F(7), etc. in terms of how it effects the results of the game? How can I possibly make this determination without knowing more details? And how close to reaching the max pitch count before these changes occur? Does Strato suggest I just say, well, F(7) is kind of close to F(8) so it's like kind of being at full strength, but not quite? And then F(5) must be about half strength? Not! What am I missing here? Certainly more experienced players can say more about what the differences are here. And if we wanted a non-card game where the computer makes a bunch of internal calculations about our pitchers that we can't see it kind of defeats the point of what I think people have loved about Strato and the player cards over the years. Please advise. Maybe I'm missing something (or some documentation) regarding this.

I have never seen an adequate explanation and we all have experienced strange pitching decisions. Recently, I had Seaver (S8) taken out of a game when he gave up a leadoff hit in the seventh inning. He was at F9, it was the first hit he gave up and had walked nobody, but somehow he was "tired." I try not to think about it.

I have never seen an adequate explanation and we all have experienced strange pitching decisions. Recently, I had Seaver (S8) taken out of a game when he gave up a leadoff hit in the seventh inning. He was at F9, it was the first hit he gave up and had walked nobody, but somehow he was "tired." I try not to think about it.

That is clearly the best answer to a question on this forum. "I try not to think about it."