A survey conducted by the International Legal Technology Association (ILTA), reported in ILTA, March 2005 at 12, found that even two years ago many law firms that submitted bills electronically had to comply with systems and procedures of multiple vendors. Some law firms had to cope with as many as 10 different formats. The proliferation has undoubtedly grown since those early days of electronic invoices.
What worsens this multiplicity is that even with the same software between a law firm and a law department, some law departments tweak the file formats or other aspects of the system. Thank goodness for the standardization of LEDES, but efforts to streamline the e-invoicing process may be unraveling with the profusion of systems and variations on them (See my post of July 11, 2006 on multiple e-billing systems.).