Unanswered Question #1

After discussions, there are usually a few questions that still remain
unanswered. Often they involve terms or concepts that seem to be
viewed differently by various members of the discussion group. These
different uses definitions of terms and concepts often prove to be
counterproductive and time consuming. I hope that answering these
Unanswered Questions may help to provide us with more productive
discussions and a better understanding of music as well as of each
other.

I would like to start with a term that was used as an example in a
recent post: Modal Interchange, or Modal Borrowing or Exchange. (In
this case, even the term seemed to be in question as well as the
meaning. Both the Pujol Etude and the Beethoven Sonata #23 were given
as examples of this term although they seem to be, IMO, very different
as I understand this term.

In my research, I could not find Modal Borrowing but did find the term
"chords have been 'borrowed' from the parallel minor" used in a
definition of "Modal Interchange" so I will start there.

***
Dolmetsch
Modal Interchange
Parallel major and minor keys, e.g. C major and C minor, which share
the same key note contrast with relative major and minor keys, e.g. C
major and A minor, which share the same key signature. In classical
music theory, the diatonic major and minor scales and the harmonies
associated with them are called the major and minor modes which should
not be confused with the Greek, jazz or church modes, Ionian, Dorian,
Phrygian,etc., mentioned in an earlier section.
By drawing chords from both related major and minor keys we get what
is called Modal Interchange. We can use this idea to analyse chords
where the piece is in a major key and minor chords have been
'borrowed' from the parallel minor, Alternatively with a piece in a
minor key we may find chords 'borrowed' from the parallel major. Using
our ears we can usually distinguish between the two cases. ***
<http://www.dolmetsch.com/musictheory31.htm#modalchange>

Questions:  Is this a good definition of the term as used in this
discussion and how does it apply in both the examples? Which specific
chords do you see to be examples if Modal Interchange in the two
examples above?
LJS