Good point with the consistency, I’d prefer to keep it the same every day as well. If I can get away with 10 hours without any negative effects that would be ideal for my scenario. I would be okay with the trade-offs of electricity and a slightly earlier bulb switch in that case. I have been keeping a close eye on everything since the switch to watch for exactly those signs. So far so good. In fact my LPS seem a bit puffier to me since changing. I’ve also noticed an increase in ALK consumption. I use concentrated Reef Code A and B from powder and I was at 13 mL per day for alk on Friday when I switched the lights and now 4 days later I’m up to 16 mL per day plus about 12 mLs in bump ups just to keep consistent. So I’m thinking there will be some growth improvements too...hopefully!I run the same time period and on/off times every day. I don't know what the actual duration of inhibition occurs and it's probably different for each acro.........par is a factor as well. I just know extra hours doesn't give me a benefit in growth or color.
You can watch your corals for signs.....like polyp extension on acros........ LPS won't be a inflated as they are trying to take in less light.
I wouldn't change durations over the weekend........consistency is important. I notice my acros start to show more polyp extension and the fish start to bed down about 10-15 minutes before lights go off.........they have an innter clock.
In earlier years I used to do 10 hours but over time I found there was no benefit.