From the minutes of the UBL TC meeting in Montreal 19 August 2009:

COMMENT DISPOSITION: CUSTOMIZATION GUIDELINES PUBLIC REVIEW 2

   The only relevant comment received in the public review period
   was from GKH: A customization should document its calculation
   model, as Denmark and BII do.  An OASIS TC is developing a
   formalism (test assertions) that could be used for specifying
   calculation models.  The question is: do we bring this to the
   attention of customizers, that they should document the
   calculation model?

   http://lists.oasis-open.org/archives/ubl-comment/200905/msg00000.html
   http://lists.oasis-open.org/archives/ubl-comment/200906/msg00001.html
   http://lists.oasis-open.org/archives/ubl-comment/200906/msg00002.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00000.html

   AGREED to add a short new section 1.5 (page 14) as follows:

      Calculation models

         The UBL Technical Committee does not prescribe a
         calculation model that governs how values in instances
         are calculated (for example, the inclusion of allowances
         in a line extension amount). Any actual implementation of
         UBL should document its calculation model via a prose
         description or a formal description using, for example,
         the methodology being developed by the OASIS Test
         Assertion Guidelines Technical Committee.

   This disposes of the 22 May 2009 comment from G. Ken Holman.

   AGREED to resubmit the edited CG for another 15-review.

   Regarding these comments from Stephen Green:

   http://lists.oasis-open.org/archives/ubl-comment/200906/msg00001.html
   http://lists.oasis-open.org/archives/ubl-comment/200906/msg00002.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00000.html

   AGREED not to prescribe a calculation model for 2.1.

   Regarding these comments from Stephen Green:

   http://lists.oasis-open.org/archives/ubl-comment/200906/msg00000.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00001.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00002.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00003.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00004.html
   http://lists.oasis-open.org/archives/ubl-comment/200907/msg00005.html

   AGREED that these are UBL 2.1 issues for the PSC.

   Document name: AGREED to change the title to "UBL 2 Guidelines
   for Customization, First Edition" because:

    - This edition doesn't apply to UBL 1.0

    - This edition does apply to UBL 2.0

    - Second Edition will apply to 2.1, but may also apply to 2.2,
      2.3, etc.

   The revised document, ready for its third public review, has
   been uploaded to:

   http://www.oasis-open.org/committees/download.php/33852/UBL-Customization100prd03.doc

   This will be on the agenda of UBL TC meetings in September.