deffinatly nailed it. unless your growing purple and your trying to induce the purple color i wouldn't want the temperature to be lower than 70. the higher the temperature, to an extent you dont want it to be 100 degrees, the faster the plants will grow....preferable to a 20 degree drop. There isn't any benefit from dropping temps at night all of the time afaik. The plants will usually grow slower in colder weather. There is a technique used at the end of flowering where temps are lowered to let the plant know that Fall is coming. Plants tend to respond by ripening faster, but this is only done shortly before harvest.
Separate from the air temperature is the radiant heat emitted by the lights. Regardless of whether or not the average air temps inside the grow area lower noticeably at night, the plants still get cooler. This effect usually satisfies any reasons to lower the temps at night manually so you can keep air temp steady 24/7.
try to keep temp at 80 at all times.Too high or too low temps stunt growth.The less variation the better.does any one know what temperature it should be while the lights are off im in flowering im about in the 5tth week