Holy crap... Looking at the first post in this thread, it started 5 years ago yesterday.
The good news is, today the problem is solved. Now it's time to go back and retrofit some code.
I had faked my own cheap avoider by outlining the white control lines with some navy ones and then checking for & onControl navy. If true it would switch the motion to wander for a few cycles, and then switch back to follow. It definitely wasn't pretty... and now I can get rid of it.

I'll have to get back to you on how well everything works, it looks like in your original avoider script you provided, there is the offscreen procedure that got added in from somewhere as it isn't in the sq3 avoid script. I haven't found it yet in the other decompiles you have provided but I will be looking for it... especially since I am sending true for ok to be off screen.
I am trying to get as much functionality as possible in the current templates so that I can stick up a new version of each. The goal is to get them as close to sci1.1 as possible so that a lot of the same code can be used in almost any version.
Unfortunately I am really struggling to decipher the iconBar but anyway, I am so glad this avoid business is back on track.