^-- Yes there are. The most significant caloric increase is in packaged foods. If several ingredients have more sugar/carbs than their COA and are combined it adds up. It surprises most folks that the healthy vegan snack they just ate, that's supposedly 250 calories, may be 300.
The USDA says:
Is there a U.S. labeling regulation that establishes the allowable variance for the analyzed value vs. what is printed on the label? If so, what is the specific regulation? (April 2011)
Yes, FDA regulations published at 21CFR101.9(g) specify two classes of nutrients; the allowable variance is different for each. Regardless of the class, the analyzed value is derived from a composite sample of twelve consumer units, with one unit coming from each of twelve different randomly chosen shipper cases.
Class I nutrients are nutrients added to fabricated foods for the purpose of fortification, such as vitamins, minerals, protein and dietary fiber. For this class, the analyzed value must be at least equal to the label value.
Class II nutrients are naturally-occurring nutrients. For this class, the analyzed value for the "beneficial nutrients" (vitamin, mineral, protein, total carbohydrate, polyunsaturated fat, monounsaturated fat or potassium) must be at least 80% of the label value and the analyzed value for the "nutrients to limit" (calories, sugars, total fat, saturated fat, cholesterol or sodium) must not be greater than 120% of the label value. These allowable variances are commonly referred to as the "80/120 rule."
So USDA compliance means your food can contain only 80% of the nutrients, but up to 20% more calories per serving.