Three-Act Progressions:Six thematic Sequences Relate to three dynamic Acts.
Four-Act Progressions:Types directly with a structural kind of thematic Sequence.
And what about the seven-act?
There is no seven-act structure as far as Dramatica is concerned. You either look at the story in terms of Journeys (3 narrative movements) or in terms of Signposts (4 narrative movements). Both exist at the same time. It just depends on the kind of context you prefer.
Thank you so much @jhull