Re: "I'm not sure about a title yet."
My nearest IKEA has an enormous warehouse at the end with shelves up to the ceiling. Despite that, there is more ground area with nothing on it than area with shelving. I reckon maybe 30% of the warehouse is actual shelves and the rest is aisles and area for other other things. So it's entirely possible the figures could be for the same thing, particularly if large chunks of an Amazon warehouse have spaces for forklifts to run around, packaging and assembly areas and so on.