Any idea why this OEM table is so strange?

[GMPX]

Thanks...

But I see the same number of rows (23) and columns (23) in both tables.

That is the problem, EFILive is expecting that table to be 23 x 23 for that OS, in the Van it is not but it is still plotting it as though it was. I cannot think of any sane reason GM would do that.

However, I am using the northern hemisphere standard for counting
(sorry couldn't resist; don't hold it against me. New Zealand is where I always wanted to go when fleeing the Zombie Apocalypse)

In New Zealand they only just got electricity so I'm ok with that comment , (I'm in Australia, so it's like the US v Canada thing going on down here).