Yeah, many 4-piece SCS grinders have a very fine screen. Too fine to catch all but the finest kief. Mine is sadly the same way - very little makes it through the screen. Mine is actually so clogged Its due for a cleaning (I cleaned the teeth sides, but never cleaned the bottom 2 sections)
From what I understand, the newer SCS 4-piece grinders use a bigger mesh screen to allow a bit more kief to pass through.
I wasn't aware they had two different types.
I had a diamond grinder that I dropped. Kief got everywhere and clogged the screen. I should have given it an iso bath but instead I thought I could pop the screen out because it had two rubber stoppers. I ended up denting the screen and had to waste money on the scs.
The scs is a better grinder but I if you take care of them they should last year's. My diamond grinder was like 7 years old. No issues w it just stupidity on my part.
Now I make sure to keep the screen clean by taking a brush to it over the 4th chamber to collect the kief that has stuck onto it. The brush I use has hard thistles and does a great job of getting any that gets stick on there.
I would soak my scs in iso to get it looking new again and try it if you are not already doing something similar.
It's time consuming to brush the teeth real good to get any left over product into the middle chamber. Than after you use all the product from the holding chamber you take the brush to the inside walls and screen so any kief that remained can fall into the kief catcher.
I do this every time and it's time consuming but it keeps my scs looking new and I have plenty of kief because of it. It's all part of my ritual so it's become second nature =)