Alright back from the vet the dog needed a check up and some meds.
Ok hermies. What we know is, interrupting the dark cycle can cause them to hermie. I did say can , the strain your growing has a lot to do with potential for hermie. Some strains are quite resistant to hermies. Now take a closer look at the dark cycle. When the lights go out or the sun goes down it takes plants 2 hours to fully go asleep and start making flowing hormones. If your on a 12 / 12 light cycle that means for 6 weeks now your plant or plants have been used to a 10 hour hormone making cycle. So we know that interrupting that cycle with some strains will give you a hermie.
Leaving the light on 6 extra hours means if you go right back to your regular schedule you will have 6 hours of dark and a 4 hour hormone making cycle. So what i am saying is leave them in the dark 18 hours and 16 hours hormone making period. That puts you past the 10 hour period that we know if we interrupt in some strains it will cause a hermie. As far as i know letting your plant make extra hormones will not cause a hermie. So it just seems more logical to me to not interrupt the 10 hour period of hormone making and just let it make more hormones to get back on the regular schedule. You could also just go 12 hours dark now get your 10 hours of hormones then turn on the light for 12 and just change up your scheduled to 6 hours ahead. Those are the two ways I would do it. I would never flip the lights back on flowering plants without at least a 10 hour hormone making cycle. Anyways that's how i look at it ,but it is your garden. Nice thing about gardening is you can do it how ever the hell you want to.