The Daily Value percentage is the fraction of the recommended amount one serving of the food contains. The optional table on the label provides adjustment values for a 2,500 calorie diet. As a Nutrition Wizard user you can essentially ignore this whole issue. Nutrition Wizard automatically makes adjustments. This is a challenging goal for most people.
Sugar is shown only in grams.
This number can be useful for comparing similar products when trying to find one low in sugar. Protein is also shown only in grams. By itself and without Nutrition Wizard, this is not an easy number to interpret.