OcclusionCulling setting seems to be inverted

So atm I'm running OR 9.0.1, Better Cities, and the upscaled texture pack. Obviously, when in a city, my framerate isn't the highest (with or without OR), which is to be expected with those other mods.

One thing that I've always noticed about the game even before OR, is that when I stand in the corner of the IC Market District, when I look straight into a wall towards the outside of the district, my framerate instantly jumps to 144, but when I face a wall towards the inside of the district, my framerate goes to 45. Even though all I'm seeing is a wall.

This scenario is where I thought the occlusion culling option would be able to make a big difference, as theoretically the game wouldn't have to render all that stuff occluded by the wall. Interestingly though, my framerate is around 24 with OcclusionCulling.Main.Enabled 1, and when I set OcclusionCulling.Main.Enabled to 0, it jumps back to around 45, which is roughly the same as without OR.

I would have definitely expected the opposite. Could it be that the setting is inverted? Or is OcclusionCulling just not working well yet?