If you factor in the ongoing RRD repair nightmare they probably aren't getting to keep much but since the newer models don't seem to have the problem I didn't factor it in. I also used the gross/net profit figure of 40% because I had accurate information about that for the Wii.
Presumably, Microsoft's shipping is more (larger console), they still have higher repair rates and because they are locked in a tight competition with Sony, they probably are spending more on promotion and advertising.
However to be as fair as possible I used the same ratio for everyone and kept the field level. In truth, MS & Sony lie in bed DREAMING about the kind of profits Nintendo accepts as just how you do business.