In my mindset, I set the temperature for a room once, I might modify it empirical over time, but never ever do I change the temperature in a room daily or on a time schedule. Way more expensive to reheat a room, than to keep a room at a specific temperature. Maybe other countries/homes are different, but that is the scientific consensus in Germany.
If that is the case we still have along way to go. I never heard about that yet. Here in the Netherlands the temperature is not set to a constant but also not totally to 0 at night. I always thought that it was cheaper to lower the temp a bit but not to much. But as u say the experts know best. Plain logic I think that the bigger the temp difference the bigger the loss and it also depends on the amount of isolation your room has.