Comment 1 for bug 924952

Some additional detail from the 2015 hack-a-way:

The issue is currently because of the way that acq.extract_holdings_attr_table pulls the holding data. It uses XPath to do two things: 1, get a count of holdings tags, and 2, select the code and value via the position() function. This allows the values to be shifted by the number of codes without values, causing values to be misattributed to codes. The fast fix is tell vendors to stop that, but a proper fix would require more complex XPath or rewriting the function in plperl using the MARC::Record module and friends.