From Gary Sick, two things to note in yesterday’s IAEA report:

1. Starting at about the time of the US presidential election, Iran dramatically slowed down its installation of operating centrifuges.* This led Mohammad al-Baradei, the director of the IAEA, to comment publicly that “They haven’t really been adding centrifuges, which is a good thing.  Our assessment is that it’s a political decision.”
In other words, there was no technical obstacle preventing Iran from installing many more cascades of centrifuges, which produce enriched uranium. Instead, it appeared to be sending a positive signal to the Obama administration, possibly the precursor to a “freeze for freeze” agreement (Iran freezes its enrichment program at the current level in return for US freezing of any further punitive actions, while talks proceed), which has been proposed in some quarters.
2. The IAEA paper also reported that its inspection discovered that more uranium had been enriched than shown by Iranian estimates. It is important to note that Iran reports on the basis of ESTIMATES, while the IAEA does precise measurement once a year with precision instruments. The total production, however, is monitored regularly and is under IAEA supervision during regular (often surprise) inspections. Senior UN officials were at pains to note that the mistake was the result of an engineering miscalculation and not a deliberate attempt to mislead the IAEA.  They also noted that no LEU (low enriched uranium) was at risk of diversion, and that the discrepancy will be corrected in future reports. In their report they say clearly that “the physical inventory as declared by Iran was consistent with the results of the [inspection], within the measurement uncertainties normally associated with enrichment plants of a similar throughput.” They confirmed that the uranium output was enriched at a level of 3.49% (it must be enriched above 90% to be usable in a nuclear weapon).

Update: Please.  If you haven’t figured it out yet, you must read Jeffrey Lewis’ blog Arms Control Wonk.  You’ve just got to do it.