I wonder if anyone can help. I don't understand. On the back of a box of cuppa soup (81g per sachet) it gives carbs for 100 g as prepared whch is 4.0 which i get as that is usual. Then there is an amount for per portion (250g ) as prepared and the carbs are 10.00. What is the 2nd amount for and where does the 250g per portion come from . This has been confusing me for ages. Where is the increase, surely not from adding water?