CO2 Laser alignment on mirror 3 (4 in my case)

Hello everyone, I’m having problems with the settings on an Aeon nova 14 elite.
I have set up the machine so that the laser beam goes straight from the tube via mirror 1 vertically up to mirror 2, mirror 2 to mirror 3 and mirror 3 to mirror 4 (yep, nova elite has 4 mirrors). My problem is that the beam does not hit the center of the last mirror. The nova has fixed mirrors and head so I can’t adjust that.

As I understand it, my only alternative is to move the tube, which is easily done. The only problem is that if I do this, I ruin the alignment between mirror 3 and 4. Mirror 2-3 alignment is still strangely enough okay.

If I readjust the beam alignment between mirror 3-4, I just move the beam back to the wrong place.

What am I doing wrong?

I attach a drawn picture so you can see where the beam hit on mirror 4.
That it hits a little high is no problem.

That seems odd, because AFAICT the mirror mounts /head attachment have oblong screw holes in their bases specifically for minor tweakage.

Mirror 1:

Mirror 2:

The laser head:

Good pictures of the mounts in your machine will help us see what you see and likely will produce better advice.

I had to reposition the tube in my machine to get the various mirrors off the ends of the adjustment range. It wasn’t pretty, but ended well:

I would say that if the mirrors are not adjustable or hard to adjust that’s a good thing. That hopefully means the machine will stay aligned longer.

The beam doesn’t have to hit the center of each mirror. The beam only has to go from the laser tube to the work surface without hitting anything, over the entire laser bed.

Have you reviewed Aeon’s guidance on beam alignment for your machine?