[Peleus]

MMR is only based off winning and losing, promotion is only based of MMR. Some of the actions you do will correlate with an increasing MMR, or having a particular MMR, that do not effect promotion.

I.e. win rates. As you win more, your MMR will increase, it stands to reason however that by the nature of increasing MMR through wins people associate win streaks / win ratios or even points as a factor of being promoted, when in fact it's simply a trait of increasing your MMR.

Also - win rates vs the league above. You don't need to achieve an xx% win rate against the league above you to get promoted. You do however have to have a higher MMR than the cutoff for the league (plus a confidence interval). Therefore having a positive win ratio against people with a MMR above the cut off (I.e. the league above) will allow you to increase your MMR and get promoted. Again people associate this winning against higher leagues as a 'requirement' when it's simply your MMR is around the cut off abd you're more likely to be matched against people with a similar MMR.

Read the guide on TL for more in depth info.