Per sachet = 41.2g carbs. is the value you are interested in.
... assuming you are going to eat the full contents of the sachet. The per 100g value is given purely to tick the nutritional guidelines so that people can easily compare products against each other, and the fact it weighs 244g "when wet" is irrelevant in this case, as the water you are adding has no nutritional value. HtH, Paul