You've got a couple of typos and I may have added to the confusion by being conservative and excluding the D3s.
The D3s is a half stop better than the D3 and D700 due to tweaking performance via software. The sensor itself is the same but it performs better through Nikon tuning the software.
When you start talking 1/3 to 2/3 of a stop difference, my rounding may or may not work.
The D4 is probably a half stop better than the D3s, but DxO has not tested it yet. It still has not been delivered. It could turn out to be more - 2/3 stop or a full stop. The technology as illustrated by the D7000 which has been tested is a full stop better than the prior generation, and a half stop better than _s updates.
Even if high ISO performance of the D800 is the same as the D3s, the color rendition and dynamic range are significantly better.