Date of hire has not been used to integrate seniority list for quite a while. All of the recent arbitrations have gone on a rationed basis by aircraft type. The reason for this is the disparity between pilot longevity for the different merger partners. If both have the same fleet types and length of service then DOH would come into play a little more. But when you have a younger, successful airline buying a bankrupt carrier then the jobs will be rationed based on what jobs each pilot group brings to the table.