Years ago I was stalking shelves at Walgreen when I noticed one of the brands of pretzels had new packaging loudly proclaiming that they now had 1/3 fewer calories and 1/3 less salt (really wish I could remember the brand!). We had some of the old packaging on the shelf and, being curious, I compared the two. The ingredients list was exactly the same so I looked at the nutrition information. Sure enough the new bag of pretzels had 1/3 fewer calories and salt per serving than the original packaging...they had reduced the serving size by 1/3!
So we have a package loudly advertising that if you are watching the calories or are on a reduced salt diet this is the one for you when in reality they were just telling you to eat less of their product in one sitting.