No, the link shows:
NIST redirected $3.4 million in fiscal year 2002 to begin a three-part plan in response to the WTC disaster. The agency received $16 million for the investigation in September from the FY 2002 supplemental appropriation. The FY 2003 appropriation includes an increase of $3 million.
Bolding mine. The other sums are additions to this main sum. Naturally, you wouldn't need as much money in 2004, because by then the bulk of the investigation is already done. That's the trick about reading comprehension. In other words, my mistake is that their total budget is a lot -more- than 20 million dollars, not less.
Besides, didn't you not want the 9/11 commision report anyway? Well, read the NIST report instead, then.