Reply by GaryK

The only thing I can think of is blade tensioning. I would think that if something were screwed up as far as being true or aligned that it would be consistant.

The only dynamic thing is the blade cut itself. If the tension were too light the blade could twist and cut both ways like you describe.

Try slowing down your cut, use soft wood, and then re-tension the blade in that order and see if you can narrow it down.

-- Gary - Never pass up the opportunity to make a mistake look like you planned it that way - Tyler, TX