I'd guess that you get this same error from a lot of places in z/OS, just not with ASMA999U as the prefix. Searching for "WRONG LEN RECRD" gets a lot of hits.
Perhaps you ought to focus on the area that is likely to be changed (the documentation) rather than one that isn't (the code). The doc for ASMA999U ought to be improved. It should mention this extra information courtesy of the SYNAD processing (or at least point to a place where the extra information is described, and that description ought to explain what it means and in this case give some of the obvious examples). Peter Relson z/OS Core Technology Design
