H'm. Reading again, he's not saying it doesn't move. Right?
He's saying the ideal location of the line could be further up or down the strap.
There is no evidence of overheating. The line on the strap electrode that is near the weld
is sometimes interpreted by tuners to be evidence of the ideal ignition timing. The rule is
often quoted as being to adjust the timing so that the line appears in the middle of the
bend of the strap electrode. I do not agree with this theory. There is ample evidence from
improved atomization style burns that this line exists only under some conditions and I
have not been able to establish a link to the optimum timing degree. It is not as simple as
that.