Hey why not use date of hire for any at AA. I hired in as a fleet service. Worked 5 years, got my A&P. Went to Aircraft Maintenance. Worked there for 5 years while working on my flying. Then I went to flight and now am a pilot. I bring 10 years with me. Now I become a 737 captain because my seniority with the company dictates that. I'm sure many other pilots will be happy that I jumped in front of them with 5 years throwing bags plus 5 more changing tires and brakes. Classification seniority is the best and fairest way. The way AA does it is fair.