Not to pick a nit; but date of hire is first day of Indoc. One of my best friends received his letter just after me, and is nearly 100 numbers senior (post merger) because he got in the previous class. It is a distinction new pilots don't make, but once they figure out how their seniority is effected they will think about it once a month for the next 30 years.

I will say there is something good about career progression. A pilot's relatively rapid rise will keep their nose in the books and their study habits fresh. IMHO the most challenging pilots to fly with are those who are returning from an extended leave where they did not even think about airplanes for a decade, or more.