tachograph:
If you have a 15 minute break at exactly 6 hours working time (say at 10:00) you will need another 15 minute break 16:15, 6 hours after the last break ended.You don’t need 30 minutes break before going over 9 hours unless that’s your total working time.
I obviously didn’t make it clear, as at bang on 6 hours I’m thinking about heading home! 
I know, unheard of… 