“Works. Selections” is a conventional collective preferred title for an incomplete compilation of works by one creator not in a single form such as Plays, Poems, etc. In RDA 188.8.131.52.3, this is an alternative to recording the preferred titles of all the individual works. Under the attached LC-PCC PS, LC practice is to follow this alternative, but PCC practice is not specified. When constructing access points for works additions to access points are made as needed to differentiate, using one of the options under 184.108.40.206. Conventional collective titles are not expressly treated as an exception here, nor under the associated LC-PCC PS 220.127.116.11. I think your analogy to expressions holds, but I can’t find an explicit statement of LC policy/practice such that “Creator. Works. Selections” is not given further qualification and might represent more than one such aggregate work. Their training powerpoint on Compilations (updated August 2013) might clarify: http://www.loc.gov/aba/rda/Refresher_training_dec_2011.html
The Access Points for Expressions task group treated titles and access points for works (including the above) as out of scope. That said, there may be particular expressions of such aggregate works, in different languages, content types, etc., at which point 6.27.3 comes into play by adding expression-specific elements (as constrained by LC practice or not) to the access point for the aggregate work (which may or may not contain its own qualifying elements).
Paul Frank mentioned recently in a message to PCC-List on October 2 that "There is still a need for the issues and recommendations raised by the PCC Task Group on Expressions to be formalized and incorporated officially into PCC documentation. I will raise this issue with the PCC Policy Committee."
In the meantime, whatever LC’s practice is, as I understand it, PCC members generally have the option to apply access points for works and expressions when LC would not, and at a greater level of differentiation than LC would require. Per the DCM-Z1 introduction, NACO members may contribute authority records for works and expressions “as needed for cataloging” even when LC would not. BIBCO/CONSER members must support all access points in PCC-authenticated records with authority records.