I find the Dramatica definitions of Instinct and Impulsive Responses to be so similar that I'm having trouble distinguishing them. In fact in Peter Shaffer's analysis of "Amadeus" on the dramatica.com website he uses them almost interchangeably.
Overall Story Signpost 2 as it relates to Impulsive Responses:
Mozart's behavior is unthinking, selfish, instinctive and thoroughly irritating to those around him. He cannot help himself, and those around him have just as immediate reflexive responses to him. They can't stand him. He is vulgar, conceited, rude, and insulting.
At the same time, his music is just as instinctive. As Salieri describes it, "It seemed to me I had heard a voice of God..." Mozart's music is something mystical that comes from beyond himself. And Salieri is the only one who can hear it for what it is. And it is Salieri's instinctive response, his instinctive understanding that Mozart's music is so rare that drives Salieri to the edge of despair.
I'm hoping you can shed some light on where the meaning of these two terms differ.