In most regs, the second stage seat is in contact with the orifice under spring pressure. The pressure is greater in unbalanced second stages than in balanced second stages (and there are some designs that remove the pressure on the seat when the reg is unpressurized, but they cause more problems than they solve).
The result is that between being adjusted at the factory and making the first dive with a customer a seating groove will develop. If the tech at the factory did not properly anticipate this effect and detune the reg slightly to compensate, it will need adjustment.
Ideally a shop will re-tune it before they sell it, or at least have a tech tune the regs after thay have been in stock a few weeks (after most of the seating groove effect has occurred) but I don't know of many shops that actually do that.