There are a few curious things there. First one being the way the ability has been coded; why not use a simple function instead of such horrendously large and unnecesarily complicated wall of text? Stuntime = distance/300 would allow for much more precision and simplicity.
Edit: Actually the target- and proxy-entity dependent script could be replaced with one that calculates the distance based on the time javelin has existed.
The second curiosity regards the distance dependency. The four last values are 1050, 1300, 1450, 1500. (250, 150, 50 being the differences) So what I'm wondering is wether this is just a mistake or is it intentional?