I believe the box comes with 14 ounces. It says on the box that it has 7 servings. Yes, I divide it in half. We each end up with 1 cup of cooked pasta. 1 cup is the recommended serving size for pasta by the USDA.
When you add bread and meatballs it is quite a filling meal.
The kids are boys, 10, 8, and 5. The eight year old will eat himself sick, the 10 year old and five year old are much better about eating proper serving sizes. none of them are starving by any means.
You're right about the 1 cup serving size but you can't get that for 5 people if you only cook half a box with 7 servings in it.
As far as using coupons to cut grocery bills I don't find them very helpful for food items since they're mostly for processed stuff we don't eat that much of and what we do eat rarely has coupons. I do use them for household products and can save quite a bit since all our grocery stores regularly double up to 99 cents.