@ slowmo
Well, I was going back further than 2012. Kowenicki has a thread where he compares shipped vs sold for the past 1 1/2 - 2 years. That's where I get the historical data from. 360 and PS3 have been undertracked for at least 2 quarters.
I do believe it would have been a lot easier to adjust the 360 sooner, since we do get concrete shipment and NPD numbers for it. Of course, now that we have the full FY shipments from Sony, and can compare it to last year's number, we should be able to get all sales somewhere in the ballpark of reality.