The meaning of "lightmap resolution" is inconsistent between meshes and BSP surfaces

When you increase lightmap resolution on meshes, you increase the density.
When you increase lightmap resolution on BSP surfaces, you decrease the density.

Also, the StaticMeshActor detail view lighting tab says “Light Map” while the BSP surface resolution says “Lightmap”

It’s been like that for as long as I can remember. Always thought it odd, but I’m used to it.