Kurantar

What is the purpose of going for the Air Combo>Zweikasu ender rather than just using JS>JH for hard knockdown? It only seems to give slightly more damage and about the same frame advantage on knockdown. Trying to figure out if its worth it for me to figure out character specific ways to end in Zweikasu from Midscreen Level 2 Low Mist Finer combos, or just save them for the Level 2 Mid corner combos.

So should I be trying to get them higher or lower if Zweihander is hitting twice? I don't see anything in the wiki about what determines how many times Zweihander hits.

I have been trying to do the midscreen combo from starting position into level 2 high mist finer, coin, dash jump air combo (jpks djksd zweihander). This is on Sol. Sometimes the zweihander hits twice which prevents the hard knockdown but sometimes it works correctly and only hits once. What determines if the move hits twice. Does that mean I am too close? What can I change in the combo to make sure that it only hits once ?