Ranked Balance is different in different regions

Ok so I just finished my first 10 ranked games in both LAN and NA. In BOTH I got 5-5, i used about the same champs and got almost the same kill/death ratios; I even fed on purpose in one match in LAN. Now the problem: having about the same scores, with one feeding match in LAN, I reach Gold III in LAN, and Silver III in NA. I don't understand how this works, even though in last season I had Gold II in LAN and Gold III in NA; meaning there isn't much difference. Why did I not reach Silver or Gold in both, and got a complete tier difference?