Has anyone considered a tax season effect on these results? I used to work for a computer manufacturer that also did re-seller / refurbishing of used computers. December was always when the seasonal tax preparation companies (Jackson Hewitt Liberty Tax), would pop up buying loads of cheap semi-reliable used systems. These tax preparers would then rent whatever cheap strip mall space was available, stick 20 PCs and a few used HP laser printers and connect them all to a decent terminal server.

The small company I worked for would sell a couple hundred of these tax prep systems a year just locally, multiply this out across the US and this could be a correlation. Many of these systems get reloaded, updated and then pulled back off the web to be resold after tax season. On company we sold them to would even let people use a part of their return to buy one of the systems.