I don't think there needs to be a temp drop. I never saw that there needed to be a big one. The plants like Heliamphoras, Highland Neps, and Darlingtonia go in the chilly window. My other Highland Neps are RIGHT next to the Fluorescent light, so, when the light goes off, the heat does too, so it's hotter there so they should experience a big enough drop.
I never encountered anything for Cephs though, I hope that just the light it's near going off is enough. If it needs a big drop, I won't change anything, as it'll be outside in 2 weeks or so hopefully.