The announcement is still the same and they will tell "everyone" you were disfellowshipped for apostasy regardless of a last minute DA.
If you WANT to attend then have fun. Why not in the meantime start writing to everyone you know (EXCEPT the elders) telling them why you are disassociating - before the announcement.
If you really want to yank their chains then don't give them a letter of DA - just appeal in writing six days after they tell you you are DF'd and include a paragraph telling them you are consulting a lawyer to look into the possibility of suing personally any who serve on the committees especially the person who announces it. Great fun.
This will buy you a few more days/couple of weeks while they consult the branch and let you send yet another letter to all your contacts about how you are being hounded and conspired against by false witnesses and how they should contact jwfacts.
Personally, if I wanted to go out with a bang then I would ignore their request for a JC and just start telling "everyone else" in writing (put your name but don't sign the letter) you are leaving due to disgusting child abuse cover ups and false prophecies about the generation!