HOW do you SKIP divisions???

Hi I'm just curious, i won 9/1 placement got placed in silver 5. Then i get +28lp per win yet when i completed S4 promo i didnt skip to S3. Anyone know why? Someone told me if you get more than +25lp per win you can skip division. Or dO u have to win every-single game from 0lp to 100 lp plus win promo in order to skip?? Anyone know how this works?

And if you want to say that my mmr isnt high enough then why am i getting +28lp?

Anyone know how to skip divisions? Im just curious thanks! :)