It might not be a problem with the tuner itself, but more the refresh rate of the screen, or the internal architecture UI refresh rate. The needle jumps about like a mentalist in an owl costume, and often I end up overshooting when I'm tuning.
I don't have this problem with the Axe3 or QC, or Polytune. Only the Helix. Haven't tried a Boss tuner for a while so can't remember how good they are.
I play in drop-B, drop-C, and I also sometimes drop the C to a G, so GGCFAD.
But hey olive branch... the worst tuner ever invented is the one on the GigRig G3. Such a massive waste of development time!!