I am currently trying to put a UITableView in a different location rather than at the top of my view controller. With this said, it is trying to add the header
In my case I was using a container view.(Main View --> Contaner View --> UITableView)
The extra space at the top, I think, is like space of the device notification bar (where the time is displayed, the battery). I really do, it's not an assumption.
What I did was from the UI Builder: