DLightContributionCulling

One thing that particulalrly spoils immersion for me is the way certain shadows pop in at close range to the aircraft.
I hadn’t noticed this entry under {Shadows in the UserCfg.opt until today.

Can someone explain what it does and whether it can be manipulated?

{Graphics
Version 1.1.0
Preset Custom
{Texture
MaxAnisotropy 16
Quality 0
}
{SuperSampling
SuperSampling 2
}
{Terrain
LoDFactor 1.000000
}
{ObjectsLoD
LoDFactor 2.000000
}
{Shadows
MaxSliceCount 4
Size 1536
DLightContributionCullingThresholdS0 0.100000
DLightContributionCullingThresholdS1 0.100000
DLightContributionCullingThresholdS2 0.100000
DLightContributionCullingThresholdS3 0.100000
OmniContributionCullingThreshold 0.020000