Setting accurate focal length with the 18-55mm f2.8-4 R LM OIS Lens

I just bought a used, but barely used, mint condition XF 18-55mm f2.8-4 R LM OIS lens. This is the second Fuji zoom I ever owned and the first was the kit lens that came with the XA1 that I briefly owned back in 2014 and remember little about.

Today I took the 18-55mm out for a test drive on my X-T1. If I set the zoom ring at 18mm or at 55mm, that is what the exif data showed after I downloaded the images. But with 23mm and 35mm marks focal lengths were slightly off the mark. I did some testing at home with the zoom ring settings at 23mm and 35mm and I couldn't get an accurate match; either fraction under or over. Plus anywhere between the four FL numbers would be a total guess. I did not see any indication in the EVF or the LCD telling me the FL setting and going through the menus, I couldn't find anything to turn on to display that. So, am I missing an option to turn on or is that just the way it goes with Fuji zooms?

It's the same with Sony cameras. You can see FL only after downloading in PC. Not sure why, camera surely have this information, but simply not display it. At the end it doesn't matter, but would be nice to see it.

You can only view the focal length of a photo during playback. Hit the display button till you see the RGB histogram, then up twice and you'll see the EXIF details, including the focal length in mm.

I don't think it's possible to preview your focal length before taking a photo, but either way why would you need that? Just zoom for the framing you need. A couple of milimeters here or there won't make a significant difference