That's because you are looking at the (print) DR figure, which is where DxOMark really cooks it up.
It's called normalization. Would you compare the times of two cars one to go 0-60 miles per hour and one to go 0-60 kilometers per hour directly without conversion factor?
You can't directly compare 22.3MP against 6MP as if the noise was all at the same power scale.
Or maybe you thought the D700 had much better SNR than the 5D2?
DxOMark claims to be testing the sensor, yet they come up with Print results?
The reason I changed to screen is Dynamic Range doesn't change with the number of megapixels. Normalizing for Dynamic Range simply hides the fact that DxOMark can't fully decode the CR2 files, by making it look like their Dynamic Range reading is changing when it isn't.
A more accurate analogy would be comparing the 0-60mph times of a two seat car and a four seat car, would I 'normalize the results' with some conversion factor because the four seat car can carry twice as many people to 60mph in the same time? You and DxOMark might, but, I wouldn’t.
Whether the D700 or 5D Mk II is better is an extraneous argument that has nothing to do with the fact that DxOMark cannot fully decode the CR2 file.
You keep talking about all the tests that have shown that the DxOMark dynamic range scores are accurate. The only tests I’ve seen that ‘prove’ DxOMark focus on the shadow end and show that using a 3rd party RAW decoder you can pull more shadow detail out of D800 or other Sony sensored cameras. Shadow recover is shadow recovery, and only addresses half of the Dynamic Range of the camera, which includes highlight retention too. I’ve seen no tests that compare the dynamic range of a 5D Mk III using DPP as the RAW converter. The closest thing is DPReview’s Dynamic Range Tests which use the cameras JPG engine for RAW conversion. Those tests show that without any electronic enhancements on that the 5D Mk III has more Dynamic Range than the D800, and with D800s ADL on that it has about a 1/3 of a stop more Dynamic Range than the 5D Mk III with HTP on. This is certainly not the 2.7 stop advantage indicated by DxOMark (D800 – DxOMark Maximum Dynamic Range (screen) 13.23 vs .5D Mk III – DxOMark Maximum Dynamic Range (screen) 10.97)