What it is trying to do is keep a constant angular relationship between the cutter centerline and the point of contact with the surface.
This is to prevent the center of the cutter from doing most of the work or to prevent a climb cut becoming a conventional cut on a downward slope or visa-versa.
So, yes, there will be Y and Z axis movements.
If you can ZIP and attach a copy of your file and post processor with the .txt file, I will be happy to look at it for you.
Can't promise a really quick turnaround, but, I will try.