I also want to comment that I have had a script work on Friday and not on Saturday - with no changes at all. OFPScript (?name? heh, why not) is even weirder than JavaScript.
I thought it was just my lack of 1337 5cr1p71n9 5k1115... *sigh*. And it probably is.. ;D
The only thing I can suggest about helos is.. If you *absolutely* have to have them do *EXACTLY* what you want, and you have no extraneous factors that might screw the whole shebang (like people shooting at them).... Don't ask the AI. It gets *far* too excited about being told to move somewhere.
You need to use a progressive setpos. Telling helos to move is accurate to within about 30 meters only, and they don't slow as they approach a waypoint.
If you don't know what I mean by a progressive setpos, take a look at the way this script handled it for picking up vehicles with a helo.
http://www.ofpec.com/editors/snippet_view.php?id=41I warn you however, this approach requires a lot of work and patience - you end up feeling more like you're making a movie than a mission. The comments in this script are informative however. Setting helo speed to "LIMITED" may also help a little, as it will reduce overshoot - but you've probably already tried that one.