Sorry for bumping, but I was looking for the same thing and found the solution.
It requires you to modify engine source files. Il post the file name followed by modified code lines:
\Engine\Source\Runtime\Engine\Classes\Engine\RendererSettings.h
ConsoleVariable = “r.MobileNumDynamicPointLights”, DisplayName = “Max Movable Spotlights / Point Lights”, ClampMax = 100,
\Engine\Source\Runtime\Renderer\Private\MobileBasePassRendering.cpp
static_assert(MAX_BASEPASS_DYNAMIC_POINT_LIGHTS == 100, “If you change MAX_BASEPASS_DYNAMIC_POINT_LIGHTS, you need to add shader types below”);
here below you should an option for 100 like its said in the comment above, like its added below
IMPLEMENT_MOBILE_SHADING_BASEPASS_LIGHTMAPPED_PIXEL_SHADER_TYPE(LightMapPolicyType, LightMapPolicyName, 2)
IMPLEMENT_MOBILE_SHADING_BASEPASS_LIGHTMAPPED_PIXEL_SHADER_TYPE(LightMapPolicyType, LightMapPolicyName, 3)
IMPLEMENT_MOBILE_SHADING_BASEPASS_LIGHTMAPPED_PIXEL_SHADER_TYPE(LightMapPolicyType, LightMapPolicyName, 4)
IMPLEMENT_MOBILE_SHADING_BASEPASS_LIGHTMAPPED_PIXEL_SHADER_TYPE(LightMapPolicyType, LightMapPolicyName, 100)
IMPLEMENT_MOBILE_SHADING_BASEPASS_LIGHTMAPPED_PIXEL_SHADER_TYPE(LightMapPolicyType, LightMapPolicyName, INT32_MAX)
\Engine\Source\Runtime\Renderer\Private\MobileBasePassRendering.h
#define MAX_BASEPASS_DYNAMIC_POINT_LIGHTS 100
Also in your project set max movable spotlights to 100 - I have not tested what it would be if you set it to 5-99, may be a problem there.
So far I have tested with 8 point lights - all working fine, no fps drop.