I understood it the way you described as well.
I thought the person that wrote the Florida Stand Your Ground legislation has said that it doesn’t apply to Zimmerman.
The part of the Stand Your Ground law that says there is no duty to retreat from anyplace you lawfully are does not apply. So, the "stand your ground" part of the Stand Your Ground law is inapplicable.
For reasons unknown to me, people also refer to the statutory immunity for justified use of force in self defense as "stand your ground." I call it immunity. It's wrapped up in the same body of law, Chapter 776 of Florida Statutes, that is commonly referred to as "Stand Your Ground."
Florida criminal law practice allows a person who is charged with the unlawful use of force, to claim the use of force was justified under Chapter 776. This "your use of force was justified" conclusion can be obtained in a hearing before a judge, and even if the judge doesn't grant it, a defendant can assert self defense at trial.
The burden of proof is on defendant to show his use of force was justified. he must produce a preponderance of evidence in favor of self defense. Preponderance means "more likely than not" or roughly 51-49, it was self defense.
If the judge rejects the claim immunity because the force was a justified matter of self defense, defendant can appeal the hearing result. An appellate court will overturn a trial judge, if the trial judge does not have clear and convincing evidence that the use of force was not justified self defense.
Any hearing in this case will come sometime after October 3. I'll be surprised if there is an immunity hearing before next year. All the players are deliberately slow-walking the resolution of the case.