Making a new akk to fight noobs and get incredible stats is called smurfing.
Abuse is mostly used to say loss abuse, yes. The amm is made so that the more u lose, the weaker you match and vice versa. If you just quit 10 games you will have at least 6 of them bad opponents if not more. Since AMM matches you with similar stats imagine u make 0:7 , you may match 0:3 , then 0:2, then 1:3, 2:5, etc. And then when u make 7:7 even ur next opponents are weak so you can make like 13-15 wins in a row. I made a whole guide for AMM in another forum.