Specifies the number of samples to use for Light Probes relative to lightmap texels. The default value is 4.
This value is a multiplier on the directSampleCount, indirectSampleCount and environmentSampleCount. This is used to account for the fact that Light Probes will have to sample a larger area than a lightmap texel. If you increase this value, the quality of your Light Probes might improve, but baking takes more time.