Let's say there are two commercial fishermen. Both earned the same amount of money, and both were put out of work by the oil spill. After Fisherman A realized he wouldn't be able to make any money fishing, he went out and scraped up another job to tide him over. Fisherman B had no such luck. He had to move in with family, waiting for better times to return. Under the rules for distributing $20 billion in BP claims money, anything that Fisherman A earned by hustling to land another job will be deducted from his total payout.