Still the question: what is "market value"?
Microsoft may simply say that the market value of a certain version of Windows (say a Laptop Edition) is $10 for a copy, and that this is to be sold pre-installed on hard disk only. Then they have the Full Version - this is sold to retailers at $100 a copy, in fancy box with CD, making the market value of this version at $100. It's easy to argue that this are different versions of the software. They may even add/remove functionality to these versions. Different product, different price.
Or how about MS declaring the market value of the software to be $10, with digital distribution, and then selling the installation keys to OEM manufacturers only with restrictions on resale (only to be sold bundled with something else). Then if MS sells the same with box and CD to retailers at $100, that'd be above market value, right? That $90 extra would cover the cost of the box design, the material for box/CD and printing cost, the transport cost, handling, etc.
Figuring out what "market value" for a product should be is ambiguous and arbitrary at best. Just look at those "anti-dumping" charges the US likes to put on various Chinese made products. The US government declares these products to be sold at "lower than market value" or "lower than cost" - no idea how the US government can really know the cost of production of a Chinese company.