These are the tracks for which the mixes were changed:

Pledging My Time
Visions Of Johanna
I Want You
Leopard-Skin Pill-Box Hat
Temporary Like Achilles
Absolutely Sweet Marie
4th Time Around
Obviously 5 Believers

In many cases there are fairly clear reasons why the original stereo mix might have been judged unsatisfactory, particularly in comparison with the finished mono version.  These include "Pledging My Time" (fade cut too short), "Visions Of Johanna" (illogical instrument panning, mistakes on lead guitar), "I Want You" (muddy sound), "Temporary Like Achilles" (fade over-extended) and "4th Time Around" (unwanted organ track).

The details are discussed further under the relevant track titles in Part II of this essay.  The revisions pick up on some of the detailed edits made in the final mono mixes, but not all of them.  Possibly this is because the more revealing stereo format would have made some of the edits difficult to accomplish unobtrusively; or perhaps they were just overlooked.