I went on a 5 win streak and then a 6 win streak and gained 15 LP for every win (with one 14LP)

Context:

5-win streak: I am Gold 3 and was duoing with my Silver 4 friend so I sorta get why it was low gains on this one

6-win streak: I was duoing with my Gold 2 brother so I don't understand why I still continued to go up 15 LP for 6 wins in a row. That means it takes 7 wins in a row to go from 0LP to promos. That's hell

(P.S. I went down 20LP for the couple losses after these streaks)