You do get more space. It's on the "north" side. The current problem with the Level 3 warehouse is that there is supposed to be a Gate B for Orders, but that is not showing up.

引用自 pseudoswede：

You do get more space. It's on the "north" side. The current problem with the Level 3 warehouse is that there is supposed to be a Gate B for Orders, but that is not showing up.

Could you please post a screenshot?
I had my Level 2 warehouse maxed out with shelves against all the walls. So, naturally, when I upgraded to level 3, I expected to see an expansion somewhere. And to my disappointment, nothing has changed.

Go into Warehouse Edit mode and, using keyboard controls only (don't change camera angle) go Up/North. If you filled the walls with shelves then from the ground you might not be able to see the new space beyond your wall of shelves.