Hwoarang's JFSR

So Hwoarang's JFSR, I've been playing hwoarang for a long time and I just can't input this for the just frame version.

I'm on a PS4 controller.

When I'm in Right Foot Forward stance, I can input it quite consistently, but from neutral it never works. It's always either a regular sky rocket, or it just thinks I'm doing forward followed by df4 by itself.

Is there any tips you guys have to help me get this right?

This is how I usually end up doing it neutral, and never works, I think I'm too slow?

But in Right Foot Forward, this input ends up giving me the just frame, so why cant I do it from Left Foot Forward/Neutral?

Any help appreciated