Recently taken receipt of my Mergress, and 'getting to know it' - seeing how it operates with different blades, settings etc. But can't quite get my head round the thing about lining up the notches. Yes - I do line them up, cos I've been told to but, looking at the cap, I can't see what difference it would make having it round the other way! I guess there are some subtle mechanics at play here that are simply passing me by... can anyone explain this in layman's terms please?