stupid timer

Hi, i got a stupid timer which will only let me do 12.25 / 11.75 will that make a difference when its time to put it into flowering mode? 4 tabs on my timer = 7 hours ive got my flowering mode on 17 hours on / 7 hours off is this goiung to effect out ?

i wont effect it if its on 12.25/11.75 when flowering ..plants can adapt...plants outdoors adapt to the light cycle neways it wont effect it

i have got up to 14.5 hours of light