Where is my LP?

Hello, I don't usually write on the board because if there is a problem with League of Legends, I've just come accustomed to not seeing that its solved. But this time my panties are in a fat knot. WHERE IS MY LP? I've played around 30 games of league in the last few days and in these ranked games i've garnered an average LP gain of around 13-14 EVERY SINGLE GAME. Problem is, I have won at least two thirds of the games and the amout of lp I get per win hasn't changed at all. I understand that there have been issues with lp gains before in high elo, but this is sad. The ranked roles was a mistake but I can almost 100% say that the LP system for high elo is fucked. I'm diamond 4 and i'm a kat onetrick with a 58% winrate on kat and 50% over all. I get it if the 50% would lower it, but it shouldn't make it much less that 18, especially cause i've been on a hot streak. I see no change in my LP gains universally and i'm almost convinced its a bug or something. Does anyone in high elo experience this problem either? Can I get a Rioter with atleast half a brain to explain why this is happening?