Hi Weebee,
Sorry to say, but "If it ain't broken, don't fix it" is a saying from somewhat old people who lives in fear that it's always going wrong...
(Sorry Brent, this is not a personal attack... I always respect your opinions... and living in fear isn't your stile.)
That docking station is for AF fine tuning.
Where you can "AF fine tune" your lens at only one spot in your camera, you can "AF fine tune" in your 150-600 lens at 16 (!!) places.
You also can tweek some AF settings and Image Stabiliser setting.
In addition, you can also install new firmware. If you haven't a docking station, you have to go to your dealer or a service centre.
I have that 150-600 C lens right from the start, the firmware update did the AF improve a lot. And more with the use of the Sigma TC-1401 1.4x extender.
If you have a lens, which you can tweek with a docking station (Tamron or Sigma), it's a must to have it.
Use such a docking station and you are in control.