Alright, let me explain this very slowly, in terms even you can understand:
This is a sportscoat:
whereas this, by contrast, is an overcoat:
Usually, the former can be worn year-round in all but the hottest weather, whereas the latter is layered over the former during colder weather.
Now, look carefully at those images. Is the second one made by just taking the first one, and stretching it lengthwise? (and then cutting the sleeves down to make them the correct length)? Of course not! They are totally different cuts and styles altogether.
Or to put it more plainly, suppose you have roast chicken with spinach and potatoes as an entrée, and an apricot crumble with clotted cream for dessert. Do you get a meal by just putting the two of them in a blender, whizzing to kingdom come and calling the meal "entreessert"? Of course not!