Well it might be because neither congress or the president is informed until CFIUS reaches a conclusion. Its to prevent bias politics. However politics did not allow the second 45 day review. It wasn't security at all or they would have allowed the check.
Executive Order. The Committee on Foreign Investment in the United States ("CFIUS") was originally established by Executive Order 11858 in 1975 mainly to monitor and evaluate the impact of foreign investment in the United States. In 1988, the President, pursuant to Executive Order 12661, delegated to CFIUS his responsibilities under Section 721. Specifically, E.O. 12661 designated CFIUS to receive notices of foreign acquisitions of U.S. companies, to determine whether a particular acquisition has national security issues sufficient to warrant an investigation and to undertake an investigation, if necessary, under the Exon-Florio provision. This order also provides for CFIUS to submit a report and recommendation to the President at the conclusion of an investigation.
In 1993, in response to a sense of Congress resolution, CFIUS membership was expanded by Executive Order 12860 to include the Director of the Office of Science and Technology Policy, the Assistant to the President for National Security Affairs and the Assistant to the President for Economic Policy. In February 2003, the Department of Homeland Security was added to CFIUS. This brought the membership of CFIUS to twelve under the chairmanship of the Secretary of Treasury. The other members are the Secretaries of State, Defense, and Commerce, the Attorney General, the Director of the Office of Management and Budget, the U.S. Trade Representative, and the Chairman of the Council of Economic Advisers.
OK one last time. CFIUS ok'ed the deal. They reached their conclusion in lightning fast time not even using the full 45 days review. The deal was ok'ed by the P&O company shareholders. The crap hit the fan only when the story gained national media attention thanks to the Internet and blogging. So from your post you state that the President or his admin had to have been notified of the CFIUS decision. Now the President and Sec Snow say they didn't know about it. So either someone broke the law or someone is lying or they are so clueless that they were notified and forgot. Knowing politics I would say someone is lying to try not to appear weak on national security. I'll leave you to figure out who is lying.