The IRS computers (programing is a four and one half month effort on an archiac programing language for which there are few remaining programer's out there) and paper forms have all been prepared on the basis of a $74,450 exemption.
The statutory exemption at present is $45,000. If not changed prior to December 31, IRS computers will not accept electronic filings.
Refunds on early returns fund much of the economy in the first quarter of the year. There will be no refunds until the computers are rewritten and paper forms are replaced--that can no longer be done before April 15.
Further, the IRS expectation is that people who want and need the refunds, when their electronic filing is rejected, will then file paper returns to get to the head of the line for refunds. IRS no longer has the capacity to accept any real volume of paper returns.
This dovetails onto discussions with my CPA of the letter the IRS has sent Congress and the facts you mention on their "code" have been discussed before. Also discussed were the IRS forms with "reserved" held for lines since they do not know what will be from Congress. I also heard Tax Pro's may not have what they need from Congress / IRS codified in software for Pro's and or Turbo-Tax type programs re-writes until March... What say you?