Going into flowering... urgent

Im growing in a soil/perlite/vermiculite medium.
400 w hps
2 11w CFLs
i had my veg schedule at start 6am end 12am
When i proceeded to switch the timing to 6am to 6pm the power must of went out last night when i woke up the lights were off..
so at 10am i turned the lights on, should i start my plants at 10-10
or should i do something else, just dont want too much stress going into flower

You should be fine for 1 day. As long as you got extended dark and not extended light. Actually the extended dark may help your plant kick into flowering gear a little. Make sure lights still go off at 6pm if thats the time you want your schedule. Also make sure it's not a problem with your timer.