I am making oatmeal on the stovetop and the container says to mix 1 cup of oats with 4 cups of boiling water and simmer for 30 minutes (steel cut oats in this case). Question: if I halve the ingredients and do just 1/2 cup oats and 2 cups water, do I also halve the cooking time to 15 minutes or does it still need the full 30 minutes?