I've been wondering this for a while with both Logic's built-in tuner and the D'addario clip on tuner I have as well.
I have a bass that is tuned drop G# to get a nice sub bass to songs but both tuners just refuse to pick it up, the lowest I have seen it is an A. Why is this? I would understand the clip on tuners difficulty as the sensor used to pick up the frequency most likely won't be that precise. But logics one? Is there a way to get around it without having to resort to harmonics and octaves?