That is correct. Basically think of it thematically. You are on the floor above shooting over the balcony. You can't just jump off - have to walk around, but you can shoot down.
Hope this helps
I totally think of it as you've thematically described but in doing so I ran into another interesting question.
Take tile 16a. If a figure is in the zone to the outside left of the blue area and another figure is in the zone to outside right of the blue area, do they have LOS on each other?
It makes sense if the figures in the blue zone can see "down" and vice versa. But the figures on either side should not be able to thematically see each other. How about from a game mechanics point of view?