If an item of food is stored for a long time, the nutritional values might reduce. Other processes such as freezing, thawing and cooking will also have an effect on the nutrition. Thus the figures given on the box are correct at the time of packaging. The figures at that time might be different from when you actually get to eat the food. In the case of your macaroni, it could absorb or loose water while in storage so the % values would only be correct at the time of packaging. Thus "as packaged" is a reference to the time of packing not the packaging itself.
As to the low fat content, dried powdered foods usually are low fat as it is difficult to make the powder with fat. They will probably have used a hard, low fat cheese such as Parmesan, or a cheese flavouring, rather than Cheddar.
You should generally trust the USDA. They've put a lot of effort into getting everything accurately measured for nutrition labeling, and in the US at least, pretty much everyone gets their nutrition data from them.
That's true in this case: the bodybuilding.com nutrition page says "This database contains data from the U.S. Department of Agriculture, Agricultural Research Service." So there's no good reason they should disagree with the USDA - if they do, I'd assume it's because their data is out of date, or they miscopied it from the USDA database.
That said, the differences are pretty tiny (pretty much insignificant in this case), so assuming they haven't made any big mistakes, you should be fine using either - it's supposed to be the same data. (Personally, I would much prefer the USDA's website or http://nutritiondata.self.com/ because they're a lot easier to read than that bodybuilding site.)
Best Answer
Carbohydrates and added sugars have different Daily Values (DVs). The DV for added sugars is 50 grams, 69g is 138% of 50g, so 138% of the recommended DV. The recommended DV for carbohydrates is 275g per day, and 69g is 25% of the carbohydrate DV.