Minor or major title change?

With v. 31, no. 1 (2006), the Journal of collective negotiations in the
public sector (ISSN 0047-2301) changed its title to Journal of
collective negotiations. In the Library of Congress bib record (LC
control no. 73640321), this is treated as a minor title change:

246 1  |iIssues for <Vol. 31, no. 1-   > called:|aJournal of collective
negotiations

I'm wondering why this qualifies as a minor rather than a major title
change. The second paragraph of AACR2 21.2C2.a) reads: "Consider also as a
major change the addition, deletion, or change of any word after the first
five words (the first six words if the title begins with an article) that
changes the meaning of the title or indicates a different subject matter."

Perhaps this is a question of subjective interpretation, but to
me "collective negotiations" does not mean the exact same thing
as "collective negotiations in the public sector." Furthermore, the
Editor's Notes in v. 30, no. 4 (2005) and v. 31, no. 1 (2006) point out
that the title change is accompanied by a broadening of the journal's
scope, and a move to make it "a general interest management and labor
relations journal..."

Many thanks in advance,
Dorota Laska