the elo system is broken. the last two games ive played ive had three people leave within the first 5 rounds leaving us to get destroyed. one would think that if someone leave you would lose little to no elo,however, in the last two games ive dropped 60+ elo due to people leaving. Also, no matter how good you do, you will also lose more elo than you gain. I was on a 8ish game winstreak gained around 130 elo then went on a 5 game lose streak and lost 180+
With 8 win streak you got +191 elo. With 4 loses you got -102 elo.
You need to pay attention to the average team elo! You will understand that each match is unique.