I think we should clear up one major terminology point here: you keep referring to a horror tale – tales have fewer requirements. Grand Argument Stories are the bread and butter of Dramatica, usually called GAS or just Stories. But never tales, which are by definition incomplete stories.
Being able to distinguish between the two becomes easier with time, so if it’s not readily apparent, don’t worry because it will kick in soon.
One of the key differences is thinking of “what ends the conflict” and “what ends the movie.”
I could easily think of a story that begins with a group of friends, specifically a writer, who go out to a cabin to put a screenplay together, get surprised (and killed) by a psycho and then kill him and emerge out of the snow drifts back to the main road – alive and safe! I could even see telling this story with some sort of redemption theme – a previously successful writer feels dead inside and needs to produce something so he doesn’t feel irrelevant, has this experience and comes out feeling rejuvenated and alive.
This has an arc, it has redemption, it has action – could be a good movie. What I’ve described isn’t a story really. Not yet, anyway. It’s a tale.
The reason I’m saying that is because it starts with one goal – write a screenplay – which gets abandoned for a second goal – survive. The screenplay becomes irrelevant.
I’m not saying that this barebones outline could never be constructed as a GAS, only that I haven’t really demonstrated the key points that would make it one. This is sort of the issue with the examples you are putting up here.
My advice is this:
Take your “get a tan” movie.
Ask yourself: what is the thing that everyone in the story is thinking about?
Ask yourself: what is the thing that only the Main Character is concerned with?
Ask yourself: What is the thing that the protagonist is concerned with? The Antagonist?
Then put those into a synopsis and add it to this thread.