I'm not really a planner when it comes to screenwriting.
I prefer to just crank out a first draft and then figure out what it's all about.
Which is why using Scriptplanner for 'reverse planning' is useful.
What I have found is that if you go back and plan a script you have already written, Scriptplanner (using AI) does a very good job of telling you what you could do to improve your script.
Then you can compare this to what you actually wrote.
Apart from giving you ideas about how to improve your script structure, what these ideas can also do is validate what you have already written in your script because Scriptplanner has not actually read your script only your plan for it.
I found it works well for my scripts and will may well do the same for yours.