Whether a Main Character eventually changes his nature or remains steadfast, he will still grow over the course of the story. This growth has a direction. Either he will grow into something (Start) or grow out of something (Stop).change in nature. He grows in his resolve to remain unchanged. He can grow by holding out against something that is increasingly bad while waiting for it to Stop.
As an example we can look to Scrooge from Charles Dickens’ A Christmas Carol. Does Scrooge need to change because he is excessively miserly (Stop), or because he lacks generosity (Start)? In the Dickens’ story it is clear that Scrooge’s problems stem from his passive lack of compassion, not from his active greed. It is not that he is on the attack, but that he does not actively seek to help others. So, according to the way Charles Dickens told the story, Scrooge needs to Start being generous, rather than Stop being miserly.
A Change Main Character grows by adding a characteristic he lacks (Start) or by dropping a characteristic he already has (Stop). Either way, his make up is changed in nature.
A Steadfast Main Character’s make up, in contrast, does not change. Still, he will grow by holding out for something in his environment to Start or to Stop. Either way, the change appears somewhere in his environment instead of in him.