All a split duty does, if achievable, is increasse the subseqent rest period ... I don't know the schedule but lets say they commence duty ay 1600, operate an evening rotation, take a split duty remaining on FDP until off duty the next morning at 1100, that's a 19 hour dury period requiring a 19 hour subsequent rest period and in my day they could only work 90 hours in a fortnight ... Would you like to borrow my calculator?