pleaseplease help me understand

Using Excel spreadsheet, formulate a diet (DIET A) for weaned pigs (7 - 11kg body weight). Design this diet to meet or exceed all nutrient requirements. Minimize excess nutrients in the diet as much as possible. The diet should include barley, corn, soybean meal, wheat, fish meal, dried whey, and soybean oil. If needed, add monocalcium phosphate and limestone to meet the Total P and Ca requirements. Soybean meal should be fixed at 30% or less of the diet. Soybean oil should not exceed 5%. Use salt to meet the Na and Cl needs and should not exceed 0.5%. Fish meal should be included at 3-6\% of the diet and dried whey should be included at a maximum of 40% of the diet. You may use synthetic lysine, methionine, threonine and tryptophan, but the inclusion of each of these should not exceed 0.5% of the diet. Amino acids should meet or exceed the SID requirements. Finally, include a vitamin premix at 0.25% and mineral premix at 0.1%. Lactose content in the final diet (DIET A) should be fixed at around 30\%. Use DIET A as reference and formulate two more diets (B and C) with the following restrictions: DIET B should contain around 25% lactose; DIET C should contain around 40% lactose. What are your observations