@Flexy:
You're right! It totally crashes!
I looked into it now (I never ran jobs before) and it crashes because VirtualDub calls my functions in a slighty unpredictable order (EndProc is called before StartProc and InitProc). Next version will be able to cope with this (I'll send you an unofficial version with a fix by email soon too).
@Warp:
I'm not completely sure I completely understand what you mean, but I think so...
It never snaps back to the 0 position during a single processing. You'll need to split the processing into several parts in order to do that.
Yes, a 0,0,0,1 row is the same as if the row was missing.
The only zero-crossings are the first and last frames that were processed in pass 1 (unless you use adaptive zoom, then there are none).