The message
from "." contains these words:

That's right - deform the pipe. The olive will be pressed into the
pipe, deforming it in a ring all the way round.

What's wrong with that?

1/ it's copper /tube/

2/ if the olive deforms the tube the joint is over tightened and will weep

Well, I've never had a compression joint leak and those I've taken apart
have all had the olive pressed into the tube slightly. If that isn't
deformed I don't know what is.
I'm using "deformed" in the sense of "taken beyond its elastic limit".
You may be using some other meaning.

--
Skipweasel
Pay no attention to that man behind the curtain.