We're working on it.
It isn't as simple as going to idle when the setpoint is reached. Consider that an overshoot is still going to occur if it goes to idle once setpoint is reached. To eliminate it the feed has to be dialed back ahead of hitting setpoint. This is not an easy thing to decide in a controller with limited information. People do this all the time, but they either consciously or unconsciously take into account a lot of information that the control simply doesn't know.
Also, if you go to idle, then the stove will eventually not be producing enough heat to maintain temp. What should happen then? Max fuel? Ramp up? How long should it ramp up? To eliminate the undershoot the control would have to anticipate the temp falling below setpoint and preemptively stoke up. Remember, it is preemptively stoking down too. And you are trying to maintain temp setpoint as closely as possible, so you shouldn't me moving more than a degree off setpoint in either direction, which isn't a lot to base control decisions on without a high precision temperature reading and even with high precision you are stimied by the slow reaction time of the fuel, the unknown damping the stove body creates, and the unknown heat circulation charateristics of the house, the weather outside (wind, sun/cloud cover, etc. all play into heating response of the house), etc.
It is all a matter of compromises on responsiveness to fast changes vs tracking of long period changes vs limited information and ease of setup vs cost. We've got a number of ideas on how to improve things, but its taking longer than we had hoped to come up with a good solution.
Plus we're trying to run and grow a business, which isn't always all its cracked up to be.