Hi,

I am attaching working script (works in Blender 2.80). Made it for myself, but it would be great if you could use it/modify it, and put it in the Magic-UV as standard option.

I use it to move UV faces to -1.0, 1.0f UV range, since on mobile graphic hardware there are issues with UV precision when large numbers are used. With this add-on, UV faces (centers) are moved closely as possible to center 0.0f, with preserved tiling (for test use box or smart unwrap, scale it to be larger than image in UV editor and select "DS offset move faces" from unwrap menu in edit mode).

With this add-on it is possible to preserve tile mapping of detail textures (grass, stones, metal
etc.) on large game level meshes (which were initially mapped with some other automatic option) and have UV coordinates moved to acceptable UV range for mobile devices.
uv_offset_move_faces2.zip