What Does Xq Mean In A Certification?

Cjd and IBFS, google "Philatelic Foundation Grading Manual" and access the item high up in the returned list that is not a website but instead is a PDF file. The PF evidently doesn't have the latest version of their grading manual up on their site. From the latest version:
"The final grade of a stamp is determined by
assigning an initial grade based on centering and
margins and then, if needed, adjusting that grade to
reflect the various additional factors just described.
Important factors such as jumbo margins or other
exceptional characteristics are not included in the
numerical grade but designated separately with a "J"
or "XQ" designation."

Thanks. Here is a link to the pdf for anyone who would like to look but isn't inclined to search:

http://www.philatelicfoundation.org...-booklet.pdf

Looks like this answers it. Thanks to everyone who contributed.


-IBFS

The "problem" with the grading used by the 3 bigger expert services that grade, is that they are unwilling to grade a stamp that falls "in-between" two grades, being better than say, a "90" but not quite good enough for "95". So if they would be willing to grade "in-betweeners" with an actual numerical grade, say 93, it would probably solve the problem. I know of several big retail dealers who have lobbied for this change, but the services won't do it, preferring to stick to a 5-point space between grades. The "XQ" by the PF was their way of (hopefully) helping to solve it.

So what I do if a stamp falls "in-between", I grade it thus "90/95" which clearly indicates it's better than 90, but not good enough for 95. While that may be a bit of a cop-out, as I could as easily started an "exact" number grade ("83", etc), I did not want to start a policy that completely conterdicts what the other services do, so I think my solution is pretty good!

How finely does one split a hair?