LP gains/losses problems

Basically was just going to ask if this is a common problem people have, or if anyone has heard of this. Basically, to start off, I get 15 lp a win and lose 22 lp a loss. However, even with this natural disadvantage, I have stayed at my rank, I have even gone on a 6 and a 7 winstreak recently. And throughout all of this, I would never gain more than 16 (usually 14) and never lose less than 20 (usually 21). I already put in a report to riot support and they said the system is working as intended. So am i supposed to take OP.gg with a grain of salt? It says my mmr is higher than average for my rank. Does anyone know if demoting to silver temporarily fixes this?

Just thought of this, what games does op.gg take into account for mmr calculation? just ranked solo or what?