It was even closer in October 2011 through December 2011 (12/12/11) which was the last week I calculated.
There is some small variance between taking the percentages you get from the TN DVD and BD units vs the Nielsen Videoscan unit marketshare BD percentages but it looks pretty random. Just what you would expect.
The unit calculations also are close but different if you take and extend the Nielsen Videoscan index numbers down vs the The-Numbers Blu-ray estimates, with small but random variations and if you go title by title and derive a Blu-ray estimate by going off the TN DVD estimate for each title and applying the NV Blu-ray marketshares. More variation for lagging BD genres with small random variations . Again pretty much what you would expect.
The recent The-Numbers Blu-ray numbers and percentages for UNITS seem reasonably accurate and at least scaled to the same magnitude as their long term DVD estimates since 2006. But I fully agree that the revenue estimates which we have no way to compare against on a weekly basis by title are more problematic and even if the best available are still less reliable.
Estimating revenues especially in the short term is always far more difficult for packaged media sales because of the difficulty of estimating Walmart sales revenues. That's always the issue, especially for a short term weekly basis.
But units should be easier at least since the fall when Walmart's share of Blu-ray sales has closed to be close to its long time 40% share of DVD sales.