I would be interested in seeing what your setup looks like compared to mine. I am only putting out 25,000 lumens with the light setup that I stated. With only having four lights, I dont think thats too bad. Would that have something to do with the longer flower period in your opinion? Im currently growing a couple blue dream and a couple skywalker. Actually I have noticed that the kush strains, like skywalker, take even longer. Maybe like 25-30% longer vs 10-20% longer with others.
When in flower i use 4 of the huge homedepot 65 watt bulbs (10,000 lumens each) and 2-4 26watts (1,600 lumens each) this set up is for scrog tho. I really like the big bulbs they just cover so much more area especially if you use a reflector or place them horizontally. i will try and borrow a cam tomorrow to take a few pics of the cab im talking about.
As for the longer flower period how tall are your plants and how many u got?id use10,000 or more lumens per plant so about 6 cfls per plant.
It sounds like a lot but its necessary.
What are you growing in? Are you using nutes? I notice cfls take a lot longer to flower a plant the taller it is, which is why i feel scrog is the way to go for cfl grows. With an even canopy, you can focus all your lighting on the screen vs wrapping your plant in lights.
soil grows can take longer because of improper ph balancing and contaminates in the water or overfeeding causing your plants to kind of lock up and stop progress. My water is filtered, airated and ph'd before touching my plants. now im just rambling but hope i helped.