That's odd. Your original problem does sound like a reg problem...maybe sticking or something internally that needs to be worked a few times before the POI is correct.
Inside the reg is a piston that has a small o ring at the top and a larger one at the bottom, (normally) 8 belleville spring washers sit on the piston. If it was my rifle i would replace the reg o rings and bellevilles and set to 85 bar on the reg checker. If you have the reg checker and the parts this is an easy job to do. It's a pity you're so far away as i could have serviced and set your reg for you. At least that way it wouldn't be expensive and it's something that you can remove from the equation. It would be really interesting to see what the chrono reading would have been for the first few 'dropped' shots.