Going above 8 or 10 micro-steps is a wast of time - literally, as you just reduce speed and torque available.
Micro-stepping does increase smoothness but there are limits.
Most machines just cannot get this resolution mechanically anyway and all that happens is if you command 1 microstep nothing happens, 2, 3 4 and possibly on the later ones it will jump to make up as it overcomes stiction.

Unless you have a really well built machine with absolutly no backlash and are in a temperature controlled enviroment trying to achive fine tolerances just will not happen.

Welcome to the real world.