3-1 of the contract which is public on Compass MEC > Home

Longevity accrual for a Pilot will commence from the date a
Pilot’s new hire class begins, herein referred to as his “date
of hire” or “EDAP.”

That sounds like it is open to interpretation to me, I would put my lack of money on management interprets this to mean when you start class one month after orientation. Honestly though I don't know yet, im sure someone can chime in with their experience on it.