I did no verification on whether that metric is correct or not, but I would suspect the metric would be only measuring the amount of revenue the IRS "generated" from doing manual work like audits. The regular, I owe 1,000 in taxes, and I paid 1,000 in taxes. Wouldn't be considered +1,000 in that case, it would be excluded from the metric altogether. Only the additional "findings" from audits would be counted.