Nope.
Extend that formula for a three day run:
Monday 12 AM: 6 ON, 12 OFF, 6 ON
Tuesday 12 AM: 12 OFF, 6 ON, 6 OFF
Wednesday 12 AM: 6 OFF, 6 ON, 12 OFF
12 hrs light for the first day,
6 hrs of light for the second day,
6 hrs of light for the third day.
You'll lose 12 hrs of light in that 36 hr...