I read full of your post, and I am glad to see, that your trying to learn, though I really can not see why your trying that. Anyway, You can`t learn whole of the game, even when BBs would explain you that. I am not watched your games, but to your question, there may be several answers. For example: Opponents had good mood, cause they won last game, you choosed wrong tactic, different enthusiasms, there were some changes in your team recently, what made your players more effective/uneffective, less audience(also if 0.5% was in home games, but the 0.39% was in away game), and then the random factor(if there is it). There are more of these factors, but I just don`t know more.
Hopefully that helped.