Champion Mastery

Not sure where to put this question but this board seems most appropriate to me

I've enjoyed seeing how the champion mastery grades me after a match and I think its great for people like me that know we aren't the best and we would like to see how we can improve. The only problem is that sometimes I'm not sure why I got the grade I did. I wish there was a way for the game to explain why it came up with the score that it did. What did I do right, what did I do wrong? A little analysis, even if its general, would be great.

Thanks for your time