It doesn't exactly line up with the bottom one either; the baseboard sinks into the floor.
If it weren't for that little patch of flat floor going past the metal divider, I'd say to vertex-edit your walls down so that each vertical edge is 256 units tall, then using the Fit button in the texture window to make both walls measure so they stretch perfectly from the top to bottom edges. Then manually set the horizontal scale back to .25 or to match the vertical scale. Then, vertex edit the top edge down again so they reach halfway to the ceiling, duplicate them to form the top half, and change that texture to the plain tan wall.