You know that's a good question, the guys at the mill claim they have been using it for years to figure how much feed and how long it will last for guys and they claim it is pretty close, as far as water consumption goes I wouldn't have a clue, I water in bulk and just top the tanks off when I get a chance with the hose. I think one tank is 85gal and the other 140gal. As far as the feed goes I feed the little ones in buckets for the first few weeks when I get em home so the get used to me and then I fill my 500lb self feeder so they are on full feed the rest of the time I have em. The other issue is with the weights, the only time my pigs are weighed is when they are hanging, I estimate the weights the whole time they are at my place. I have an average of how much feed total it takes me to get 40lbs pigs to a 300lb average. I basically posted the chart for a reference for someone getting pigs for the first time. It helped me determine what size water tanks I needed cause I had no clue how much water a pig needed, it gave me an idea of how much feed I needed to buy to get me thru the first two weeks or month. For someone starting out not knowing a thing about hogs the chart helped me make multiple decisions. Hopefully it can help someone else too. I would be interested to see if someone weighed their feed daily and their pigs weekly and compared their findings to this chart how accurate it is for commercial feed. So I guess my answer is I believe it's pretty close but I don't have any hard numbers to back it up, just estimates. Make sense?