Preheat oven to 425 degrees. Line two large baking sheets with parchment paper. Stir flour, 1/3 cup sugar, baking powder, salt, and baking soda in large bowl to blend. Add butter and shortening- using fingertips, rub in until coarse meal forms. Add 1 cup buttermilk and stir lightly until dough comes together in large moist clumps. Gently toss in blueberries. Gather dough into ball. Transfer dough to lightly floured work surface. Gently knead 3 or 4 turns to combine well- careful not to mash blueberries! Divide dough into two balls and flatten each ball into 3/4 inch thick rounds. Using floured knife, cut eat round into 8-10 wedges. Transfer wedges to prepared baking sheets. Brush each wedge with remaining 2 T. buttermilk and sprinkle with sugar. Bake scones until light gloden brown, about 15 minutes.