Summicron-R 90 hood mystery (figured it out)

EDIT: Nevermind, I figured it out. The inner/lower part of the lens hood had a very thin ring you could unscrew, then slide the trim ring+barrel in and reattach. It now works, though I wonder why the heck someone took it apart to begin with!

Sorry for all the help threads posted lately, just got back into analog gear and going through a big pile of acquired equipment (couple of estate sales). I have a 2-cam Summicron-R 90 as well as what appears to be two pieces of a sliding lens hood.

I figured that the front trim ring unscrews, the two pieces of hood fit into each other, the entire mess is shoved onto the lens and the trim ring reattached.

Works fine, the hood slides out like I'd expect, however it seems to keep me from hitting infinity focus. I really don't see a way to get a better fit since the lip of the trim ring has to sit above the inner/lower hood piece and at that point there's simply not enough space left on the barrel for the hood (short by about 1-1.5mm).

What the heck am I missing here?! If you look at the first image, there's a felt ring on the inside and that part sticks out a couple of mm too far past the barrel of the trim ring for the entire mess to be screwed down all the way while retaining infinity focus.