sensor plate stopper

[Alan L]

I ordered and received from Pelican a sensor plate stopper - part # 911-1101961-00. For my 930 with an '87 spec engine.
As far as I can see the same part number is listed for 911/turbo models right up to 86 and beyond. There only seems to be the one sort.
When I try and install it, I have about a 10mm gap between the stopper and the bolt head in the top of the plate. I'm not sure how it is supposed to work, given the fine settings on the air plate, but somehow I figured it was to stop the plate from bashing upwards on nil throttle. But it would have to go beyond closed to hit the stopper.
Any clues?
Alan