When I ran Lint on a file of records, one of the errors I received was "250: Subfield _b is not allowed." According to the most recent documentation, 250$b is $b - Remainder of edition statement (NR). I do not know when this change took place, but it has been around for as long as I can remember (though my memory only reaches back to 2000), and according to a colleague, it was in place for a while before that.
Thank you for your assistance, Bryan Baldus Cataloger Quality Books, Inc. The Best of America's Independent Presses 1-800-323-4241x460 [EMAIL PROTECTED]