So, if, when making soap, I have a total oil, water, lye weight of 90 oz., and I assume 12% evaporation of water after curing 6 weeks, then the total weight, without fragrance oil, would be 79.2 oz. Then I calculate 6% of 79.2 oz (4.75 oz.) and add 4.75 oz fragrance oil to the oils, water and...