It's also worth nothing that while USCIS may have plenty of EB2 cases, they may have told DOS that they intend to use only a subset of the remaining visa numbers, leaving the rest to the consulates. If the consulates don't have enough cases to handle and need more to use up the numbers, then DOS needs to move the date forward to ensure that the numbers get used.
I think this view of RelaCanadian is more dependable. The date progression may be related to push & pull from the consulates than USCIS. This makes sense now.
I think John thomas view is not accurate enough(there are so many cases eb2's pending , check this forum threads- and approvals have been like less than 50 cases as per the tracker). I can believe your view if they atleast approved 50% of the applications for the 2005 cases before going to 2006. you are trying to present more rosy picture of the situation. We will know in October for sure Eb2 is going back to 2004 or 2005 or 2006