All Things Event Hacking

I'm having trouble clearing an event code and I was hoping someone here could clue me in.

What I'm trying to do - The event checks if Terra is in the party. If so, when Leo's sword is clicked, the party fans out and watches her say a few words and flash the screen while she chants. Then she pulls the sword from the grave, the sword disappears from the map and gets added to the parties inventory. Then, clear the event bit (1F20 bit 0 according to ff6le), collapse the party and continue on.

Now the event itself is working, what is NOT working is the event bit to keep the sword "gone" on return visits to Thamasa. I thought command D1 9C would clear the proper bit (09C 93:4 Leo is buried in Thamasa; disables the scene with the imprisoned Kefka), but... it doesn't.

If anyone could help me understand the relationship between 1f20 bit 0 in ff6le and 09c from the event bit list I'd be really grateful. I have also considered setting my own event bit (11A A3:2 Unused? seems safe) and adding a check to the Thamasa entrance event to simply delete the sword on load, would that be more practical?