    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  postal service to explain unavailability of  the data.