Low day temps in late flowering?

So low temps are supposed to bring out the colors, I get that much. Due to my location and the heat I run my lights at night. Obviously the way nature has it, it's hot during the day and cold at night, but with my grow it's hot at lights out and cold-er during lights on (78 lights off, ~76 lights on)

My question is, if I wanted to cool my grow to bring out colors, it'd have to be during the lights on. Would having it down to ~60 during lights on and ~78 during lights off make my ladies upset?

Oh and I've got 2 weeks till harvest!

You need the cooler temps during lights out to bring out the color. I think an even temp would be acceptable in your case. Not as colorful but still good.