This is bizarre to me, I have literally never had this problem. Even if you don't have a scale, pasta is sold in standardized package weights and recipes have the weight you need so like if it says 12 oz then that's 3/4 of a 1 lb package. Then again, I always just scale the recipe to the full pound of pasta anyway because it's easier to deal with instead of just having 4 oz of pasta sitting around trying to figure out what to do with.