How come it doesn't recommend using the brick pattern on the 6x24 tiles?

We do recommend a 1/3 or 30% offset when installing any linear tiles (6x24, 6x36, 12x24...etc). You can achieve the brick pattern that way. The reason why we don't recommend using a 50% offset brick pattern is because all tile has a slight crown to them and there is a minimum acceptance give for this by Tile Council of North America (TCNA). So if you go with a 50% offset, you are butting up the highest end with the lowest end, that is why every manufacture recommends 1/3 or 30% offset. If you go with the 50% offset, there is a greater chance for lipage. I hope this helps