That would be interesting. Unfortunately, MSDS that old
are not available. If it did I wonder why Kodak would change
back. Phenidone is used in one form or another in HC-110,
and the T-Max developers (it finally shows up in the latest
MSDS) as well as Xtol. However, the current MSDS for
Polymax-T and the ones I saved some time ago for Ektaflo
Type-1 show Metol, not Phenidone or Dimezone (a form of
Phenidone). At this time Phenidone containing paper
developers seem to be made by Ilford (Bromophen), Agfa,
Edwal, Sprint. Maybe others but not Kodak.

  I have no idea of what this means. My experience with
Amidol is that it produces good, rather neutral color,
prints which don't look much different from those processed
in Dektol. Amidol is not a magic developer. It is very
active, in fact, the most active of the generally used
developing agents other than Phenidone. What I suggest is
that a comparison of Amidol with Dektol at 1:1 rather than
1:2 may show less difference.
  A note about terms: I have no idea what is meant by
"narrower area and cut off in the Dmax area.
  To me highlight separation means maintanence of contrast
in the highlights. The characteristic of the paper is the
main factor in this. On paper the highlights are on the toe
of the curve. In all cases the toe has lower contrast than
the mid tone area of any emulsion. On paper this results in
some compression of tones.
  The shadow areas of a print may not get into the shoulder
of the curve. Modern emulsions can reach quite high maximum
densities, well beyond the values usable for a reflection
print. Shadow detail also depends on the contrast of the
shadow part of the print curve but is more often a result of
the toe of the film curve. In any case, there tends to be a
reduction of contrast at both ends of the range. Since
reflection prints can reproduce a brightness range of only
about 30:1 at best some compression must take place
somewhere. The eye expects to see contrast of about the same
value as in the original or the tone rendition will not look
natural. If the mid tones are reproduced reasonably
accurately the eye is generally tollerant of compression of
shadows and highlights.
  I've done actual comparisons of prints developed in
different developers and find very little difference other
than small variations in image color among them. Others may
have a different experience. The problem with internet
discussion is that there is no way of seeing someone else's
results. So much is lost or subject to variation in a
scanned image that they are not too useful for comparing
subtleties.
  I was introduced to Amidol about fifty years ago. In
fact, its a very good and simple print developer. Its
shortcomings are now mainly its cost, and its short tray
life although that can be extended somewhat by adding Citric
acid. In any case, its long enough for practical purposes.
The other drawback is the tendency of Amidol to stain
anything it dries and oxidizes on dark black. This stain is
very hard to remove so its a good idea to use gloves or
tongs and not get your hands into the stuff.