Dark Souls is developed in Japan but more of a Western RPG style(Even the original developers of Demon's Souls referred to it as a western RPG). I'd hardly call that a JRPG if we are considering the genre diference. People usually refer to a JRPG and WRPG based off of their style difference rather than where they were made. If you are going to include that you might as well include western RPG games as well if you are saying they arent different.
It is like comparing FPS and a TPS. Very different styles that are judged accordingly. Where they were made makes no difference. If japan makes a FPS game we arent to call it JFPS. We just call it FPS.