The spring aids in adjusting the intonation, (pushes the saddle forward as you loosen the screw... I always help it a bit)... Other than that, it is negligible as the string tension does a decent job of keeping the saddle in place, (as you can see... even after you're adjusting screww came all the way out, the saddle stayed!)
A bigger concern would seem to be that your saddle is so far forward on the E string...
Typically, the E string requires the longest length of all the strings to properly intonate, putting the saddle furthest towards the back of the bass.
If you've never seen it,
Gary Willis has an excellent site with intonation information... I've been doing my own setups for dog's years and I still refer to this page all the time...
-robert