    Sentence 1: 67 through .67d, provide a  mechanism for limiting the issues on    which a_trial-type hearing is required;         allow the Postal Service to explain the           unavailability of data that would    otherwise have to be filed; and provide  for data collection for the duration of    the experiment.    Sentence 2: 67 through .67d provide  mechanism for limiting issue on which  trial-type hearing is required allowing