For all these guys, DoJ will either be 1 Jan 2000 (the date of the integration) if they're ex-ASL or whenever they Joined CX if they just went there for an early command.
It sounds like the guy you're referring to was a CX F/O, took a fr8r command in say 2000-2004 and is now coming back to the pax fleet.
If he was ex-ASL then, as csd wrote, he must be one of the more senior ex-ASL guys who now hold the seniority for a pax command.