One of my first questions when re-reading this LC-PS was: whose rules, instructions are following? RDA allows us to differentiate; the LC-PCC instructions says not to go beyond $l field for authority records.
Here is the LC instruction:
When identifying an expression not already represented by a name authority record, do not add another characteristic to differentiate one such expression from another expression (e.g., do not differentiate one translation of Shakespeare’s Hamlet
in French from another French translation; do not differentiate one arrangement of Berlioz’ Corsaire
from another arrangement). Other elements in LC’s bibliographic record (e.g., translator, date, medium of performance) are available to the user for selecting a specific expression if desired; RDA 0.6.6
allows differentiating characteristics to be recorded as separate elements or as part of the authorized access points. If there is a name authority record with an authorized access point for an expression that includes an additional characteristic LC would not have added, use the form of the access point in that authority record; this action is consistent with the LC/PCC policy of using authorized access points in existing name authority records
My other questions is this: if one authority record for a an expression in the same language and also further qualified, do we have to differentiate our new entries under the same language, do we have to also further differentiate our new expression that we have in hand?