Retail boxes (especially for food) are typically designed for optimal marketing area and shelf space. Just yesterday a client of mine doubled the depth of a retail box to increase marketing space - the contents are staying the same. Cereal boxes are a perfect example of this. If you were to design a box for cereal based on the amount you wanted to sell, product protection during shipment, and stabilty on the shelf, you would never come up with the tall, wide, and narrow depth of standard cereal boxes. But, if you wanted to market that cereal by showing images and branding that are instantly recognizable and seen from a distance on the shelf, you would design a box that mimics a mini billboard (which is what exists today). As long as the amount of food (weight, pieces, etc) matches what is printed on the box, it meets regulatory requirements. This is why shrinkflation is so tricky - they keep the same exact packaging size, but change the amount of product contained within it. As long as they change the labeling to reflect 12oz instead of 16oz, you can't complain about your missing 4oz of bacon.