DoS doesn't know accurately the 140 pipeline. But more importantly what DoS calls demand is NOT a 1:1 relation of approved 140 to 485. e.g. 485 has dependents, and also that 485 needs to be adjudicated before USCIS can make a demand for a visa for that 485.
Theoretically yes everybody can do what we are doing here .. trying to predict. But as far as DoS' operations go ... they have certain rules and framework that they follow. That's all there is to it. Sometimes they will breka their own rules if not bend it to achieve certain policy objectives. So I really feel its futile to predict how far beyond will they move dates. What we can say with more confidence is how far will tehy have to move in order to consume the visas available this year.
That dates is about mar-apr 2007 for EB2.