Except that in the case of 'sugar' it's likely that at least 50% of it is fructose (if it is all added sugar) whereas starchy carbs become glucose in your body. An exception is something like greek yogurt with no added sugar, in which case any sugar content stated on the label should be lactose.

For me the most important thing about the sugar number on a food label is that it is a red flag warning me …. Be careful for herein probably lies fructose. And if in doubt I check the list of ingredients.