Revenue is the product of price times volume (R = P * V). The problem for the farmers is that because the price of cheese (P) went up, demand for it (V) went down. Essentially, the government raised prices to a level higher than what many people wanted to pay. The farmers made more money with lower prices because they sold a lot of cheese (a high volume, in the terminology of the formula). The potential for these artificial imbalances is why markets are generally more effective than governments at setting prices.