How to improve light quality on iOS

I have multiple point lights casting onto a cube. In the editor this looks nice, with minimal artefacts visible.

However, when I run the application on an iPhone the artefact become quite obvious. The light doesn't nicely fade over the cube material.

Here's what it looks like in the editor:

Here's what it looks like on phone:

I've experimented with changing the material type (currently the standard detail-diffuse), but that doesn't seem to make a difference. Both the desktop and mobile are set to run with the following quality settings:

• Pixel light count: 10

• Full res texture quality

• Anisotroptic textures: Per texture

• Anti-aliasing: 4x Multi Sampling

I've completely disabled shadows, as I don't need them for the game.

How can I make the light disperse better in the mobile version? Is this simply a limitation of the platform?