Unofficial Starfield Patch

I think this is a majority of interiors from what I've seen, which leads me to believe that it's a design choice. I would guess from a design point of view that excepting certain designed locations, they would want "normal" gravity in interiors in order to control the gameplay experience. Just go inside the Lodge (1.0) on Jemison (0.91), or inside the Frontier (1.0) or the random planetary locations such as "Deserted UC Listening Post" (1.0) when you're on any planet/moon (0.09 for example). I haven't seen it explained in the game, but I guess you can chalk it up to Settled Systems "gravity control" technology, perhaps with the idea that humans would want "normal" gravity when they go inside a location.

I don't know about anywhere else, but in Akila City there are other interiors such as The Rock which are set to 1.51G.

POIs are somewhat randomly applied to things so that may be an entirely different thing where it's not inheriting gravity from the planet properly.

So anecdotally I think most interiors in the game are 1.0 as mentioned but here is some example data from the Akila City interiors. This city is a bit of a maze, did I miss any? You can see that the overwhelming majority (92%) are 1.0, so I feel that it's more likely that 1.0 was the standard and that someone didn't get the memo, and changed just a couple of them. Otherwise if interiors are supposed to match the planet, I can't imagine the incompetence that almost every single one isn't set properly?! And this is just Akila City, I think if you check other locations you'll find a similar situation with the interiors. If only a few weren't set, I'd agree that the intent was to match the planet, but that's not the case.

Akila - 1.51
TerraBrew - 1.51
The Rock - 1.51

Akila City Consulate - 1.0
Akila City Galbank - 1.0
Akila Guard Barracks - 1.0
Akila Prison - 1.0
Cartwright Manor - 1.0
Coe Estate - 1.0
Coe Heritage Museum - 1.0
Enhance! - 1.0
Filburn Agricultural Systems - 1.0
Henry Filburn's House - 1.0
House of the Enlightened - 1.0
Lance Estate - 1.0
Langston Manor - 1.0
Laredo Firearms - 1.0
Midtown Minerals - 1.0
Sanctum Universum - 1.0
Starrett House - 1.0
Stoneroot Inn - 1.0
The Core Residence - 1.0
The Stretch Apartment - 1.0
The Trade Authority - 1.0
Weston Filburn's House - 1.0

The only time actual gravity control tech is ever mentioned is when talking about how a grav-drive will normalize gravity onboard a ship, or you end up weightless when the grav-drive is disabled. These drives take a good sized amount of energy to maintain too.

There is never any indication given that interiors built on planets would have normalized gravity. There certainly isn't any indicator given anywhere that there are gravity field generators for planet interiors, and one would think that deploying such things at scale would result in constantly shifting gravity for the people living in these places which would result in them getting sick a lot.

What I think probably happened is at some point, someone has the good idea to make interiors inherit from their parent planet, but they never updated the locations which had been previously worked on to use this new inheritance system.

If it's somehow backward though and they changed it so that you had to manually set each interior, it could be that not everyone read the email that day and was relying on it being handled automatically.

I suppose either way this is something that may end up requiring developer comment. Cause right now the system as-is makes no logical sense.

And for fun I took a quick run through New Atlantis as well... A few interiors were inaccessible from quests etc (I'm on Xbox at the moment so I can't just teleport in), but I think this is most of them:

Jemison - 0.91

Argos Extractors (Valberg) - 1.0
Armistice Archives - 1.0
Athena Tower Apartment - 1.0
Centaurian Arsenal - 1.0
CJ's - 1.0
EIT Clothiers - 1.0
Family Apartments - 1.0
Jemison Mercantile Store Room - 1.0
(MAST) Cabinet Chambers - 1.0
(MAST) Defense Research - 1.0
(MAST) Central Command - 1.0
(MAST) Vanguard Orientation Hall - 1.0
Outland - 1.0
Reliant Medical - 1.0
Residences (Orion Tower) - 1.0
Sanctum Universum - 1.0
The Lodge - 1.0
The Well - 1.0
UC Distribution - 1.0
UC Security Office - 1.0

"this is something that may end up requiring developer comment. Cause right now the system as-is makes no logical sense."

Agreed.

This might make things easier to catalog:
https://www.nexusmods.com/starfield/mods/7998