Same here Im 18/6 at for my growI would not do that.I always go 18/6 right to 12/12
that plan I follow in my grow now, I'm in the 7th day after switching to 11-1312 on 5.5 off 1 on 5.5 off 12 on for vegetation
11 on 13 off decreasing on by 30 minutes every two weeks until reaching 9 hours on for flowering
finishing is supposed to be quicker for flowering plants. i'm not sure yet as this is the first time i'm using it. BUT what i did notice, sexing time was cut down to just 4 days after switching to 11-13. if it's not a better lighting schedule, its definitely no worse and i save money on electricity.