(meteorobs) ejection velocities and ejection times

[Bias, Peter V]

Hi all,

  Unfortunately I deleted the postings that told us where to look, but we were recently directed to look up some 2004 Giacobinid and Leonid meteor shower timings at a website.  I did, and found graphics of AUs from Earth at nodal crossings, timings, etc.  Below that was a presentation of perihelion passage, ejection velocities, etc.  
  My question is this:  Are these ejection velocities the velocities extant when the comet reached its nodal crossing in those years?  After all, comets are spewing a lot of material for months before and after nodal crossings.  Wouldn't those periods need to be looked at as well?  For instance, wouldn't a high ejection velocity at one time perhaps be comparable to a lower ejection velocity at a different period in orbit? 
  Can somebody help me out on this?  Thanks.

  Looking forward to the Leonids!

   Pete Bias