Hmm, your settings seem to be the same as my settings. When I make a new event in my iPod Calendar, when it syncs any new events in my Mac iCal get transferred over and at the same time the new event in my iPod Calendar gets transferred to my Mac under my "Home" calendar. Make sure in "Advanced" that you don't have "Calendars" checked for replacing information, and then go into your iCal and delete all your duplicate calendars.