Got a friend with a smurf account but he's not that game ruining Booster/Hacker/acc buyer type of smurfer. He just created a second account himself to test how high he can calibrate (by his own, no Booster or any of that shit) after he used his re-calibrate token few months ago.
Basically, what is the mmr difference you would expect? Cause let me tell you, he's 1k mmr and calibrated with the new account to 1.5k mmr. You might say "he'll drop to his original mmr". But he's climbing ever since and sitting on 2.1k mmr now. Yet with his original account he can't win. Both accs 9.5-10k behavior score. I start to believe that mmr is not just a number but a damn false/inaccurate number as well…
I can't see any difference in his playstyle or hero choices. Yet soon 1.5k difference soon If he keeps climbing.
Source: https://www.reddit.com/r/DotA2/comments/zweyvk/a_friend_has_two_accounts/