Chipotle burritos are quite large (the graphic shows 1.25 pounds), and could easily make two meals if you were so inclined. The tortillas are bigger than "dinner plate" sized, so I can see the calorie count going up too. Perhaps they are thicker to hold together as well. You could easily make a veggie burrito exceed 300 calories, so I have no idea how this count would have gotten on the signs by accident.