The way it was put to me, by the local RFD, was to cut down the number of warranty returns of airguns, not necessarily relating to power adjustment, but any adjustment.
My Daystate MK4 ingested a pellet into the action through the pellet probe hole, he was able to take apart and remove as he had badgered DS into giving him the AT tool, otherwise it would have had to be sent back to Stafford, or the AT removed. If there had been no AT, I would have been tempted to take it apart myself, potentially mucking it up!
I would imagine manufacturers would have to test power on most regulated guns going out the door, otherwise how would they set them up?
It's the Indian not the Arrow