Been doing some digging and it seems 4444 may be overkill.  The colourspace and bit depth are higher (bit depth 12) but if this is beyond DCP is seems pointless.

Also in the preview (after file imported) when I look at same clip in 422 and 4444 the 4444 one looks pookier with better blacks and the 422 one looks a little flat/washed out.  Is this just the preview? 

Ben