My husband speculates like this....just for an idea....not that we have a clue at all!
Jeb didn't call it until he knew he would have it. And was spending the last few weeks getting that knowledge together.
Again I am not trying to raise hopes or say this is anything but pure speculation on the part of my husband.
Actually it looks like the special session had been called a couple weeks ago for another matter but he plans to use it to introduce Terri's Bill now too. (another poster said it had been called Oct 9 but i forget the issue it was called for)