Top Consistency

[Doug Hardie]

I am running FreeBSD 4.6 and top does not show consistent data (at 
least in my understanding).  The cpu states line shows the percent of 
time in user state.  I would expect the percent processor used by all 
the active processes to add up to something close to that. (single 
processor machine).  However, it never seems to come close.  Often it 
will show 25% user and the sums of the active processes utilizations 
will be around 2%.  Other times it will show 2% user and the sum of the 
processes is over 10%.  Is top wacky or is my understanding wrong?