If you work, say, a 37 hour week, but you work a 4 * 4 shift system, you will work considrably more that the contracted hours, so this becomes rostered overtime. Obviously people who work this shift system, or any other that calculate holiday in hours appear to dip out, but the bean counters claim that on a level playing field, they are no worse off than anyone who keeps regular hours. If you ask me it sux.