Sorry, can't elaborate more. That was what I was told when I did my ETOPS pilot training back in '97 in Canada. Granted, RVSM started on the NAT
's in early 1997 and maybe I was told the wrong information.
As far as RVSM goes, I was told that it was only the immediate area around the static ports that mattered. But perhaps since surface damage can also affect pitot tube airflow, most likely you're right. Especially if you're in the maintenance side. Unfortunately, the flow of info between our groups isn't as good as it could be!
Thanks for the Q,