It seems likely that should be the case, but it’s probably rare for two main reasons.
First, strong narratives are self-reinforcing. If you have a story where lots of things are off, you can tell it’s not right but it’s hard to know how to fix it. But if you have a story where everything’s right except for MC Signpost 2, you’ll sense the problem in exactly that place and intuitively know how to fix it because everything else in the story will help guide you.
Second, even if there is a whole bunch of “doing” that happens in that act related to the MC, it would be the one moment of Being that would feel important – the part of the story’s skeleton that’s discernible beneath its fancy storytelling clothes.
Now, I’m assuming that your example is talking about a story where nearly everything fits a single storyform. It is certainly likely that there will be lots of movies where creators butt heads and don’t agree on things, have different visions of the story, or just aren’t telling a solid narrative from the get-go. But in these cases they don’t end up with every story point right except one; they end up with a bigger mess.
But they’re still trying to tell a good story…
I agree that it does seem absolutely crazy and insane that Dramatica can predict what it does – until you accept that it’s a model of the mind’s problem-solving, as is narrative itself. (It was hard for me to accept in the beginning, but then I did this experiment, which had only a 1 in 32 chance of succeeding.)
I apologize that most of my post is just assertions rather than ways you can verify things yourself. Maybe we need to design experiments where we validate Dramatica statistically? I’m sure it could be done. Teams of 2+ people analyzing films independently…