Extending the use of `cs:label`

I couldn’t find any discussion on this, but I never understood why
cs:label is limited to the “page” and “locator” variables:—
label =
element cs:label {
attribute variable { “page” | “locator” }

This leads to situations like (copied from APA style):

Here cs:text is used to show the “volume” term, and cs:label to show the
"page" term. The limitation of using cs:text for “volume” is that the term
cannot be applied using contextual pluralization.

Would it make sense to expand the use of cs:label to any of the locator
variables, i.e.:


“sub verbo”

All these variables have singular and plural terms, so it would be an easy
patch. The only reason I can come up with to limit the selection somewhat is
that some of these variables may only occur as a locator.