[Bug 11664] New: 5.6.1 "word-spacing-critical-length"

http://www.w3.org/Bugs/Public/show_bug.cgi?id=11664

           Summary: 5.6.1 "word-spacing-critical-length"
           Product: XSLFO
           Version: 2.0 Working Draft
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: XSL-FO
        AssignedTo: Tony.Graham <at> MenteithConsulting.com
        ReportedBy: dave.pawson <at> gmail.com
         QAContact: xsl-editors <at> w3.org

"This property specifies a length (x) for the word spacing to allow before
invoking letterspacing. More precisely, it specifies a limitation on the effect
of a "letterspacing" value; letterspacing may be used in the line-breaking
algorithm within a given line-area when otherwise the word-spacing value would
be greater than x."

Critical is used, not max or min? No indication of which side of the value
causes a transition from word to letter spacing? A length is used, yet the
description talks of a limitation (on what?).

The requirement says "Allow users to specify the priority between word and
letter spacing." 
I'm guessing that when word spacing exceeds this value, letter-spacing is used?
1. Does it meet the requirement (no mention of which of the two has priority).
2. I don't find the property name at all intuitive wrt purpose.