Shader complexity on Mobile (Android Preview)

Anybody can let me to a Good documentation (with tutorial, please) to see how Shader complexity Works in Mobile?

I have a simple scene with all lights static, materials without lots of nodes (only texture nodes assigned to shaders) and my shader complexity in Android preview are Red/Dark Red.

I test-it into HTC Focus/Samsung RV headset, but my framerate are very low.

Thanks

PD: The Unreal documentation only explains how work Shader complexity viewport mode, not clarify all things.