Lower flow temperature for nighttime use

Our heating is working beautifully but given gas prices and the cold, we would like a more cost effective way of keeping bedrooms warm in the winter.

In practice what happens today with our tado and viessmann 200 w digital link is that the valve in one or two bedrooms partially opens every hour or so to keep the bedroom at 16.5 deg,

It seems to me that it could be effective to set the flow temp of the water to (say) 45 deg rather than 60 (which is capped in the boiler) for these periods when less heat is needed. It might help the boiler condense more.

I’m not sure of the actual efficacy of this solution but it seems logical that it should make a difference.
The system would modulate the temp up and down until the flow temp was the lowest it could be and the room(s) still maintained the target temperature.

Ps - I realise that the system will modulate the boiler already (I’ve seen it do this), but I guess I’m looking for a more explicitly aggressive mode that can be set to modulate much further down, and, now I think about it, further up if so desired (to warm a cold house perhaps)
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