Heat oven to 400°F.
In a large bowl, mix brown sugar, butter and shortening. Stir in flour, oats, salt and baking soda. Reserve 2 cups of mixture for top layer.
Press remaining mixture in ungreased rectangular 13x9 inch pan.
In a medium bowl, toss apples with 3 tablespoons flour. Spread over the mixture in pan.
Heat caramels over low heat, stirring occasionally, until melted. Pour evenly over apples.
Sprinkle top with reserved oat mixture and press lightly. Bake 25-30 minutes or until topping is golden brown and apples are tender.
Cool for 15-20 minutes, then cut into bars while still warm.
Store covered in refrigerator.