Understanding Repeatability factor of motor

[simasa]

Hello,
I am searching a very high precise and compact motor. The motors that I find offers about:
+/- 10 arcsec repeatability.

What is true understanding this term:
I cannot achieve the precision lever more than +/- 10 arcsec anyway. As it is manufacturing tolerance.
OR
I can compensate it through my high resolution encored and position control loop.



I would also appreciate some suggestion about a highly precise and small motor. Very low repeatability. My load requirement is just 5g. I need to use it for precession measurements.

Thanks in advance
simrs