There is no guarantee YCbCr444 is video level...
That is something you will have to verify for yourself.
This is actually true of ALL formats.
Profiling also has to be the same levels as the image path - TV legal or data.
It is critical you get that right.
(Most monitors/graphics cards do the rescaling automatically using EDID)
If the image path is video level you will need to use the VideoScale function on the LUT before exporting.
And yes, it should be done after all other functions.
Mob Boss at Light Illusion