When GDR3/Update 3 was released through the enthusiasts program, some were disappointed to find out that it didn’t bring the third column of live tiles to any of the currently available devices. The first device to debut with this third column of medium sized tiles was the 1520 back at Nokia World, but we’ve heard that the extra row of tiles should be coming to other devices as well in a future update. There has been a lot of speculation whether the third row of columns is dependent on the screen resolution, or screen size dependent (logically it should be resolution dependent).
— Nawzil (@Nawzil8) November 15, 2013
It seems the third option of columns was initially present in internal beta builds of GDR3, and was pulled before release for reasons unknown. Hopefully though we won’t have to wait too long to see it on our own devices.
Thanks for the tip Alvester