An accelerated crop using an 18 hour day/night cycle will achieve the same yields using a 3 week grow cycle and a 6 week flower cycle. This equates to 21 days @ 14 hours a day and 42 days @ 6 hours a day = 546 hours of light over 9 weeks resulting in a 40% reduction in power consumption and a 25% reduction in crop time.
Unfortunately this doesn't quite add up. Say you start this on a Monday at 00:00. So on Monday they get 14hrs light, then 4 dark, then another 6 of light before 00:00 on Tuesday. Then they get 8hrs light, 4 dark, and another 12 of light by midnight. Wednesday they get 2hrs light, 4 dark, 14 of light and another 4 of dark, then the cycle repeats itself every three days. this gives an average of 18hrs 40mins of light per day over each 3 day cycle, so you are actually using slightly more energy running the lights on this cycle than if you used 18/6.
Flowering, then. Again, we'll start on Monday, 00:00. 6hrs light, 12 dark, 6 more light. Tuesday starts with 12 hrs dark, 6 light, and 6 dark, Wednesday has 6 dark, 6 light and then 12 dark. Average of 8hrs of light per day.
This means that for the 3 week grow cycle, the light will be on for 396 hours, then a further 336 during bloom, for a grand total of 732 hours over a 9 week period.
I'll grant that if the rest of the theory is sound, the time saved would still save money,
if the yield was not reduced by giving them less light. They say that for the second half of the day, the plant is growing at 20-30% of it's potential, but it is still growing. Therefore if those hours of the day are not present, you are bound to lose yield. Which one of the methods would give better results on a cost/gram basis could only be determined by experimentation. I certainly wouldn't put my faith in the theorisations of someone who would overlook such a basic point in their calculations, much less if they were trying to sell me something related to the point they were trying to make.