... CBO informed lawmakers in May 2003 that the tax cuts would cost the treasury $94 billion in 2006. But it now appears that the cuts generated so much “unexpected” economic activity that the original CBO projection for 2006 was off by an astounding $124 billion! Add in last year’s underestimation of $89 billion, and the $25 billion oversight in 2004, and you have a cumulative CBO mistake that now totals $238 billion.