Poz extender is obsolete. Consider using the new, improved extender in my plugin pack on the main page. It uses a simpler, more elegant algorithm which does not require any order to your vertex selections at all. The script does not work with the latest versions of Lightwave (I think since 7.5 or 7.0b) because of changes made to the lscript interpreter.
Note: Please excuse my humble notepad-generated webpage. I am currently very busy with my classes and will attend to it in time.
Poz extender is my first attempt at an lscript. It allows you to point extend without worrying about looping polygons, unlike point extender or kag extender.
Point extender *always* loops polygons - making a nasty, unwanted polygon whenever your selection isn't circularly connected.
Kag extender, on the other hand, *never* loops polygons, leaving a gap when your selection is circularly connected. I found it to be very useful in the past, but I felt a need for something more sophisticated.
Poz extender is like a hybrid of the two. It detects whether your selection is circularly connected or not and extends out based on that information, only looping when necessary.
It will also extend subpatched polygons if the polygons connected by the vertices are subpatched. (Thanks to d|vZzilla in #lightwavers for help on detecting subpatched polygons through lscript).
Additionally, poz extender allows you to select vertices in a random order. As long as the first two points define the clockwise/counter-clockwise direction, the rest of the points can be selected in any random order (or using the lasso tool) and extended fine. It will reorder your selection basically to allow it to extend properly (see video to see how this works).
This means that it works in symmetry mode as well, since symmetry mode only presents problems with kag and point extender due to out-of-order selections. Note, however, that in symmetry mode, your first two vertex selections will probably not be in order. Therefore it may be possible that PozExtender will extend polygons that are facing away from you when you wish them to face toward you. However, I simplified the process of flipping the new polygons if necessary by making poz extender automatically select both the extended polygons and vertices after the operation. Just switch to polygon mode and tap F and the polygons will face the proper selection (note again, that this should only be necessary in symmetry mode if your selections are in order).