I've seen this term mentioned touted as the reason for a faster bow. I have been doing a bit of figuring (I have the cipherin ability of Jethro Bodine).
I suggest an arrow with a speed of 360 fps will get to a target .064 (or 1/16) of a second sooner than an arrow traveling at 260 fps. at 20 yards. IMO that is not a very long time.
I chose those arrow speeds because they represent the fastest and the slowest Xbows onCabela's web site.
Does a 1/16 of a sec give a deer a chance to "string jump"?