Shift work question for the trucking massive

Nobody seems to have noticed that there is 24 hours from shift 3 to 4…

However, if you follow the 12 hour rule, not what’s written, the end result is:
Start 0600 Monday
Finish 1000 Friday
5*8 = 40h

Week done by 10am Friday morning. Start again Monday 6am. Quite pleasant in my mind.

Why would anybody in their right mind want to work more than that anyway!