I see the point about increased possibility of cycling (ON/OFFing) of the boiler with a reduced flow temperature, but can't see why that would start separately from the boiler change. Obviously if the old boiler was underpowered, it would run flat out to try to get the temperature up whereas if the new boiler is oversized, it will have to cycle to avoid overheating. I suppose increasing the boiler setpoint will increase the required heat output, but ultimately the room will reach the set temperature and then the system will cycle instead. May be less in terms of cycling, but probably won't eliminate it.
Can you remind us what make and model boiler you have please?
Can you remind us what make and model boiler you have please?