Flex Queue

Okay, so I have been playing flex queue these past few days and I have seemed to notice that teams will not be really balanced at all. For example, the most recent one was a team made up of a Gold IV, Gold V, Silver II, Platinum V, and a Gold V vs. a team made up of a Gold IV, Gold III, Platinum V, and 2 Platinum III's. So can I ask exactly how these teams are balanced? Every game has been this way and honestly it just makes the game unbalanced as one team just steamrolls over the other.