That's a really good question and a fairly subtle one! It turns out that the northern and southern routes are symmetrical not along the equator, but along a line drawn from the subsatellite point to the point of north/south divergence, which was around 10 degrees north. This effectively rotates everything counterclockwise on the 7th arc: the southern endpoint is further north and east, and the norther endpoint is further north and west.
That's a really good question and a fairly subtle one! It turns out that the northern and southern routes are symmetrical not along the equator, but along a line drawn from the subsatellite point to the point of north/south divergence, which was around 10 degrees north. This effectively rotates everything counterclockwise on the 7th arc: the southern endpoint is further north and east, and the norther endpoint is further north and west.