[Tinfoil hat on] Playing in platoon has a different MM/RNG values than playing alone

As someone who started playing in 2011. stopped in 2013 and partially returned to the game about 2 years ago (with breaks), I know that playing in platoon counts differently, the MM is not the same (I guess that the game sees you as superior, if MM works that way at all). Most games I played in the past two years were in a platoon. WR plummeted, all other stats are steadily going up (not that I care, I'm just seeing the stats). For the last 3 days, I've had a couple of battles all alone – WR is going up, my shots are not misteriously hitting the ground right in front of the tank and I'm having far better time overall. So please tell me WTH is going on? Is the game "punishing" you for playing in a platoon, or it's just that we don't think/play as we should when we are in one (there's been some great games, but so far I could count 20 lost games on 23 played)?