I've got a roll that has been adapted for concert use.  It is not a
special Concerto roll, but a standard London-issue roll which has been
hand-edited to be, as it says, a "doctored master for concerts."  It is
roll 0208, Szymanowski Etude, Op. 4, No. 3, played by Myra Hess.

All such editing is done using Aeolian's characteristic black tape, so
this is very much a factory production.  The most obvious alterations
are to the dynamic levels, making all the middle levels much quieter in
order to compensate for the overall increase in loudness from using a
large piano.  This shows that Aeolian was well aware of the issue that
all too many concert-grand recordings of Duo-Art rolls blithely ignore,
making all the 'P' passages become 'MF' or worse.  There are also
alterations to increase the pedal bridging.

As Bob Taylor indicates, it has additional dynamic information coded
into the "stop" hole that was never actually perforated in Duo-Art
rolls.  On this roll all of these are hand-punched in parallel with
theme accents.  They are clearly intended to give an extra-loud playing
level.  Not all of them are at power 15, but they all occur where it's
obvious from the music that a particularly powerful accent is required.
I'd imagine that these trigger a crash valve or extra theme device,
instead of merely raising the theme level, because they are coded and
read alongside the note, unlike dynamic codes which are read in advance
of the notes.  The clear intention is to give a targeted extra accent,
probably in addition to the more broad-brush crash effect triggered by
the overall dynamic code on a standard Duo-Art.

Julian Dyer