Ranked AFK's

i know this has been touched on before but I thought of maybe a different way to deal with this I get that we should still lose LP but why lose the same amount? I lose 20 for the average 5 v 5 loss if I have an afk on my team why can't I only lose like 10? and the enemy team only gains half the normal amount because they had an unfair advantage and we had a disadvantage