They only angle I can figure out is that he was using that doubt against possible actions of his old enemies such as Iran, who could not know for sure whether he had them or not.
The article does raise a good point. Security systems compartmentalize information so that few had a complete picture so the could not give it all away. This tendency had to get more pronounced after Saddam's son in law defected and revealed much about Iraqi WMD programs. It is also a fact that the many operators around Saddam hustled money and perks from him and did not deliver but spun stories about how well they were doing and paid off others to keep quiet.
I doubt that Saddam had a complete picture himself, although he had supposedly total access.
I disagree. A dictator rules by knowing everything and more than anyone else completely. And Saddam even now is playing the game. He moved them out, in my opinion for an exchange of power in some fashion against America. The real question would be who would stand to gain more than Saddam to keep the goods moving?