I still don't understand MMR and Provisional's

So I was always told early on back in S3, that the lower you were in the ranked matches on the banning screen, the more MMR you would likely obtain. I understand you are going up against people that have and haven't done their provisionals as well. A few of my buddies went 4-6 and 6-4 along with even 5-5 and all got into silver 5. I was put into the bottom of the banning screens about 6 of my 10 games, and the other 4 i was second to last.

I ended up winning 7 of my 10 provisionals and got put into bronze 3. I dont understand how winning 7 of the 10 is even considered bronze? That doesn't make any sense to me because I completely skipped season 4 all together. So I didn't rank in s4, come into s5 and win 7/10 and still get bronze while my friends all got silver when they did worse? And I know they were at the bottom of their team too.

I really think this ELO thing with MMR is a joke. I seriously dont understand how I got put into bronze 3 when i know for a fact 50% fo my games played were against gold people from last season. Anyone know how?