Miss Stephanie is the neighbourhood gossip. To her, the Tim Johnson incident is something that she talk about for the next couple of days. She's is concerned about how the dog's owner is going to react once the news (probably by her) is told.
Miss Maudie is different. Like the other moments when teh kids meet with her, she uses the moment to teach Jem and Scout something about their father. Miss Maudie tells the children perhaps why Atticus never mentioned his shooting skill is the fact he has an unfair advantage over an animal. This gives the kids something to think about.