The limit of 0.0125 there indeed looks a bit arbitrary. But on a purely technical level, it can be justified: Imagine you had to draw a line on a globe, from the north pole to the south pole. Where would this line be? Note that even though you are giving a longitute in your code, all longitude values end up at the same position for the north- and south pole…
A reasonable (and simple) workaround might be to simply insert another point at the equator: