Ignoramus7337 fired this volley in
:

The trouble that I am concerned with, related to high counts per one
revolution of the encoder, is that encoder or the control may fail to
count them properly and may miss some.

Too few counts == low accuracy due to large vertical move per count
Too many counts == missing counts from time to time



If missing counts is the issue, then you have two avenues of recourse:

You can use a faster processor, so that interrupt service latency is
shorter, or you can use a hardware decoder board for the quadrature
encoder, so that any time you wish to read it, it will be up-to-date.
It's not necessary to resolve every transition in software.

LLoyd