One very important thing to remember; no 2 VITR.
VNAV does not update actual winds during descent. It has computed a descent profile with what you told it to expect, or from actual TOD wind reducing an unknown algo' to zero at ground. It needs monitoring and some help; at times.
2nd most important thing to remember is it needs monitoring at all times.
3rd most......same as 2nd!!
There in lies the most oft heard ????? from cadets. Sadly 3x anything, too often, requires a japanese brain to find an answer.