you guys realize this is an outdoor discussion right? every single day the night/day ratio is different! your plants don't need anywhere close to 12 hours of dark to flower! in the outdoors your plant will start getting ready to flower around 15 hours of daylight, the gradual reduction of a few minutes a day gently and naturally coaxes the plants into flowering the way they have for millions of years, most decent outdoor strains start flowering mid july to mid august, wich is basically the longest part of the year, and they ripen over the next 60 days as the light gradually goes down a few minutes at a time, starting with the 15 hours that it matured at to 13 by the beginning of September (so you see many ripen and finish before they ever reach 12 hours darkness) to 10 hours at the beginning of November, though most decent outdoor plants wont flower that late...
there is no set hours of light that will dictate a plants flowering schedule, and yes you can grow a plant with 10 hours of light and it will grow stragglier, and produce less, and fluffier buds than normal but you get one extra harvest a year, wich means more overall money to a comercial grower... how do you think crappy beasters are made? thats why you can consistantly buy low quality bud that smells like hay, the hairs are still almost white(didn't naturally dry out and turn brown)few tricomes...people manipulate light and harvest times to make a lot of crappy pot for a little extra money, personally i would rather produce less good bud for less money...
if you are trying to get your plants to flower early i would stick to 12/12, basically you are imitating an indoor grow but with a much stronger light...you could probably get away with flowering with 13 or even 14 hours of light for bigger buds but you would have to shorten the daylight hours to finish ripening. flowering a plant with 10 hours of light is not good though, your bud will not be as potent as if you were to just stick with a consistent 12/12 schedule, which is widely agreed to be the best compromise between having enough light to bud decently while having enough darkness to stay in budding and to ripen on time.