The dual fuel operation switch over point is only applied between heating cycles. Nest should be able to switch over during a heating cycle, which would save significantly more energy than waiting for a cycle to end and then apply the change.
For instance, over night the Heat Pump primary system has retired because the switch over point of 35f has been met and the propane (expensive) secondary heating has taken over. All is good. Come morning the system is working hard to bring the home to daytime temperature, which is a few points higher than our overnight setting.
Nest is buring propane, but the outside temperature during this cycle has crossed over the 35f switch point because the sun is up and quickly brings the outside temperature within optimal Heat Pump range. Nest does not make the change back to primary Heat Pump until it reaches the end of its current heating cycle.
We could be saving plenty of propane if Nest would act on the switch point as soon as it is reached, not waiting on the start of the next cycle. The system is unnecessarily burning propane for an additional hour or more.
This is a simple programming fix. Please see if this can be revised.
Thank you
